How Outreach + ColdRelay Work Together
ColdRelay (Infrastructure)
ColdRelay provides Microsoft 365 mailboxes purpose-built for cold email. Each mailbox is an M365 account inside an isolated Azure tenant with its own dedicated IP, fully-automated DNS (SPF, DKIM, DMARC), and a 95% inbox-placement guarantee. Pricing is per-mailbox: $1.00 (1-199), $0.85 (200-999), $0.70 (1,000-4,999), $0.55 (5,000+). Setup completes in 60 minutes with a 50-mailbox minimum.
Outreach (Sending Platform)
Outreach is an enterprise sales engagement platform — the heavyweight in the category, used predominantly by large B2B sales teams running structured outbound at scale. It handles sequences, multi-channel cadences (email + dialer + LinkedIn), conversation intelligence, and deep CRM integration with Salesforce and HubSpot. Outreach does NOT provide email infrastructure. Reps connect their own mailboxes — primarily via OAuth to Google Workspace or Microsoft 365 — and Outreach orchestrates sends from those mailboxes.
Why use them together
Outreach is the sales engagement brain (sequences, multi-touch cadences, CRM sync, analytics). ColdRelay is the infrastructure body (mailboxes, IPs, DNS). The pairing is most useful for enterprise teams that already run Outreach for their primary reps but need a separate, isolated infrastructure layer for cold-prospecting motions — net-new pipeline development, agency-managed outbound, or SDR cold-outreach campaigns that shouldn't share IP reputation with the rest of the company's email.
Connect Outreach to ColdRelay (Step-by-Step)
- 1
Confirm the integration path is right for your Outreach instance
Outreach connects mailboxes primarily via OAuth to Google Workspace or Microsoft 365. ColdRelay mailboxes are M365 accounts living inside ColdRelay's isolated Azure tenant, not your own corporate M365 tenant. Before ordering, check with your Outreach admin (or your customer success contact) whether your Outreach instance permits connecting M365 mailboxes from external tenants. Some Outreach deployments are locked to a single corporate identity provider for compliance reasons.
Note: If your Outreach instance is locked to your corporate M365 tenant only, ColdRelay mailboxes cannot connect via OAuth. In that case the practical path is to run cold-prospecting campaigns through a different sending tool (Instantly, Smartlead, EmailBison) on ColdRelay infrastructure, and use Outreach for warm-pipeline reps on your corporate mailboxes.
- 2
Order ColdRelay mailboxes
Sign up at coldrelay.com/sign-up, pick a domain (ColdRelay handles registration for $14/year), and order your mailbox count. The minimum is 50 mailboxes ($50/month at the base $1.00 tier). ColdRelay's automation provisions the M365 mailboxes inside an isolated Azure tenant, registers the domain, and configures dedicated IPs.
Note: Provisioning takes 60 minutes end-to-end. You'll receive a CSV with every mailbox's address, password, and connection details once it's complete.
- 3
Wait for DNS propagation
ColdRelay configures SPF, DKIM, and DMARC records automatically on the new domain. DNS propagation usually completes in under an hour but can take up to 24. Verify with the Email Deliverability Test at coldrelay.com/tools/email-deliverability-test — when SPF, DKIM, DMARC, and MX all show as configured, you're ready.
Note: Do not connect mailboxes to Outreach before all four records (SPF, DKIM, DMARC, MX) verify. Outreach's first-send reputation check will flag unauthenticated domains and slow your ramp.
- 4
Connect each mailbox to Outreach
In Outreach, go to Settings → Email → Add Mailbox. For Microsoft 365 mailboxes, choose the Office 365 option and complete the OAuth handshake using the ColdRelay mailbox credentials (full email address + password from the CSV). Outreach will redirect to a Microsoft sign-in flow against ColdRelay's Azure tenant. Approve the requested permissions to grant Outreach send-as and folder-read access.
Note: If OAuth completes but Outreach reports 'unable to verify domain ownership,' confirm DNS propagated fully and re-attempt. If Outreach rejects the external M365 tenant outright, your instance is locked to corporate identity — see Step 1.
- 5
Set daily send limits per mailbox to 2
In each Outreach mailbox's settings, set the daily send cap to 2 outbound emails per day. This matches ColdRelay's per-mailbox limit. Outreach users coming from corporate Google Workspace or M365 are often used to 50-200 emails/day per mailbox — that volume is not appropriate for ColdRelay infrastructure. Scale total send volume by adding more mailboxes, not by raising the per-mailbox cap.
Note: Outreach's volume guardrails (in Settings → Email → Send Limits) let you enforce the 2/day cap at the org level so individual reps cannot raise it accidentally. Use this for cold-prospecting cadences.
- 6
Run warmup separately (Outreach has no native warmup)
Outreach does not include a warmup network. ColdRelay mailboxes ship reputation-ready (the dedicated IP + isolated Azure tenant gives a clean start), but for new domains we still recommend running 2 warmup emails per mailbox per day for the first 2 weeks. This can be done via a third-party warmup service connected to the same SMTP credentials, or skipped entirely if you're comfortable starting from cold with the 2/day cap.
Note: ColdRelay's per-mailbox limit accounts for 2 outbound + 2 warmup = 4 total/day MAX. Going above that ceiling — including from warmup — voids the inbox-placement guarantee.
- 7
Build your first sequence
In Outreach, create a sequence (Sequences → New), assemble your steps (email touches + optional task/call steps), and assign your ColdRelay mailboxes to the sequence's email-sending pool. Outreach distributes sends across all assigned mailboxes respecting each one's daily limit and time-zone send window.
Note: Use Outreach's snippet and variable system for personalization. For subject-line variation (which Outreach doesn't do natively), the Spintax Generator at coldrelay.com/tools/spintax-generator produces compatible variants you can paste into A/B step tests.
- 8
Monitor deliverability and reputation ongoing
Outreach's deliverability dashboard shows bounce, reply, and open rates per mailbox. Run the Email Deliverability Test weekly to verify SPF/DKIM/DMARC stay passing. Check Google Postmaster Tools for spam-folder rates and IP reputation. ColdRelay automatically monitors blocklists and alerts you if any of your dedicated IPs hit Spamhaus, Barracuda, SORBS, or SpamCop.
Note: ColdRelay's 95% inbox-placement guarantee is contingent on following the 2/day/mailbox cap. Exceeding the cap — easy to do accidentally in Outreach if a rep bypasses the org guardrail — voids the guarantee for that mailbox.
Key Considerations for Outreach + ColdRelay
OAuth-to-external-tenant is the integration's biggest variable
Outreach mailbox connections happen via OAuth against the mailbox's identity provider. ColdRelay mailboxes live in ColdRelay's Azure tenant, not yours. Some Outreach deployments accept external M365 tenants without issue; others are restricted to a single corporate IdP for compliance. Confirm with your Outreach admin before ordering — there's no workaround if the instance is locked down.
Daily send limits per mailbox — much lower than Outreach norms
Outreach users running corporate Google Workspace or M365 commonly send 50-200 emails/day/mailbox. ColdRelay's cap is 2 outbound + 2 warmup = 4/day MAX. This is the optimal-deliverability ceiling, not a software limit — going higher burns the mailbox's reputation and voids the 95% inbox guarantee. Use Outreach's org-level send limits to enforce the 2/day cap so individual reps cannot override it.
Separate cold-prospecting infrastructure from warm-pipeline reps
Connecting ColdRelay to Outreach is most useful when you want to isolate cold-prospecting cadences from your corporate mailbox reputation. Your VPs and AEs keep sending from corporate Google Workspace/M365; your SDRs (or an agency partner) run cold sequences from ColdRelay mailboxes. Reputation issues on cold sends don't contaminate the rest of the company's email.
Outreach has no native warmup — plan for that gap
Unlike Instantly, Smartlead, or EmailBison, Outreach does not run a warmup network. ColdRelay mailboxes ship reputation-ready but new domains benefit from 2 weeks of light warmup. Either connect a third-party warmup service via SMTP to the same mailboxes, or accept the cold start and rely on the 2/day cap to keep reputation healthy.
CRM sync is the real reason teams use Outreach here
Other sending tools handle cold email mechanics better and cheaper. The reason to run cold outreach inside Outreach instead of Instantly or Smartlead is Outreach's tight Salesforce/HubSpot sync — engagement data, prospect activity, and call/email logs all land natively in your CRM. If you don't need that, a lighter sending tool on ColdRelay infrastructure will be both cheaper and operationally simpler.
Domain-rotation strategy
ColdRelay caps each domain at 100-150 mailboxes for deliverability reasons. If you need 500+ mailboxes, you'll order multiple domains. Outreach handles multi-domain sending natively — assign mailboxes from each domain to different sequences or sequence steps to spread risk across domains.
Pricing Snapshot
ColdRelay
ColdRelay's per-mailbox cost ranges from $1.00 (1-199 mailboxes) down to $0.55 (5,000+). Domain registration is $14/year, one-time. For 200 mailboxes: 200 × $0.85 = $170/month + $14 annual domain cost. For 1,000 mailboxes: 1,000 × $0.70 = $700/month.
Outreach
Outreach pricing is enterprise and by-quote — Outreach does not publish per-seat pricing publicly. In practice, expect Outreach seats to land at significantly higher per-user prices than self-serve cold email tools, with annual contracts, implementation fees, and tiered platform packages depending on features (Engage, Voice, Meet, Kaia). Contact outreach.io/pricing for a quote scoped to your team.
Total monthly
Because Outreach pricing varies by contract, total-cost comparisons require knowing your specific Outreach quote. The infrastructure side is predictable: a 200-mailbox cold-prospecting operation runs $170/month on ColdRelay. The Outreach seat cost for the SDRs running those sequences sits on top of that and is the larger line item by an order of magnitude in most deployments. For teams already on Outreach for warm-pipeline reps, the marginal cost of adding ColdRelay for cold-prospecting is just the per-mailbox infrastructure fee.
Common Issues + Fixes
⚠ Outreach rejects the ColdRelay M365 mailbox during OAuth with 'unable to add external tenant' or similar
Your Outreach instance is configured to accept only your corporate M365 tenant for identity reasons. There is no workaround on the Outreach side without an admin policy change. Either request your Outreach admin to allow external M365 tenants (typically possible but requires a compliance review), or run cold-prospecting through a different sending tool (Instantly, Smartlead) on the same ColdRelay mailboxes — those tools connect via SMTP/IMAP and don't depend on tenant trust.
⚠ OAuth completes but Outreach shows 'domain not verified' on first send
DNS propagation hasn't completed for SPF/DKIM/DMARC. Run the Email Deliverability Test at coldrelay.com/tools/email-deliverability-test against the domain. If any record is still pending, wait — propagation can take up to 24 hours from provisioning. Once all four (SPF, DKIM, DMARC, MX) verify, Outreach's domain check will pass on retry.
⚠ Mailbox connected but emails landing in spam at Gmail / Outlook
Most commonly this is the per-mailbox cap being exceeded. Verify in Outreach's send-limit settings that the mailbox is capped at 2 outbound/day. If the cap is correct, run the Email Deliverability Test — if SPF/DKIM/DMARC all pass, check Google Postmaster Tools for the domain. Sustained spam placement with correct authentication and respected caps usually indicates a content issue (subject lines, link density), not infrastructure. Use the CAN-SPAM Checker at coldrelay.com/tools/can-spam-checker to audit the email.
⚠ Outreach's bounce rate shows higher than expected (>3%)
ColdRelay infrastructure produces ~0% infrastructure-side bounces — what Outreach is seeing is recipient-side bounces, almost always from a stale or unvalidated prospect list. Validate the list with an email verification tool before importing into Outreach. Bounce rate above 5% will trigger Gmail/Outlook reputation damage regardless of how clean the infrastructure is.
⚠ Inbox-placement test (Mail-Tester, GlockApps) shows missing or failing DKIM
ColdRelay's DKIM is on the domain's _dkim.YOURDOMAIN.com selector. If a test reports missing DKIM, it usually means the test ran before DNS propagation completed. Wait 24 hours from provisioning and re-test. If still missing after 24 hours, contact ColdRelay support — there's a deliverability consultant included at higher mailbox volumes.
Frequently Asked Questions
Can ColdRelay mailboxes actually connect to Outreach via OAuth?
It depends on your Outreach instance. Outreach connects mailboxes via OAuth to the mailbox's identity provider — Google Workspace or Microsoft 365. ColdRelay mailboxes are M365 accounts inside ColdRelay's Azure tenant, not your corporate M365 tenant. Some Outreach deployments accept external M365 tenants without issue; others are locked to a single corporate IdP for compliance reasons. Check with your Outreach admin before ordering. If your instance is locked down, a different sending tool (Instantly, Smartlead, EmailBison) on the same ColdRelay infrastructure is the practical alternative.
Why would I use ColdRelay with Outreach instead of just using my corporate Google Workspace mailboxes?
The main reason is isolating cold-prospecting reputation from your corporate email reputation. If your SDRs send cold outreach from the same Google Workspace mailboxes your AEs and execs use for client communication, deliverability issues from cold sends contaminate your entire company's email. Running cold sequences from a separate ColdRelay infrastructure layer keeps that risk isolated. The secondary reason is cost — Google Workspace is $6+/mailbox/month vs ColdRelay's $0.55-$1.00.
How many mailboxes do I need for my Outreach team's cold outreach?
ColdRelay's per-mailbox cap is 2 outbound emails/day for optimal deliverability. So if your SDR team needs to send 500 cold emails/day, you need 250 mailboxes. The Mailbox Calculator at coldrelay.com/tools/mailbox-calculator lets you input your target volume and gives you the exact mailbox count + pricing tier. Note that this is significantly more mailboxes than Outreach teams are used to provisioning — that's expected, because the 2/day cap is what protects deliverability.
Does Outreach have a warmup feature for ColdRelay mailboxes?
No. Unlike Instantly, Smartlead, or EmailBison, Outreach does not include a warmup network. ColdRelay mailboxes ship reputation-ready thanks to the isolated Azure tenant and dedicated IPs, but for new domains we still recommend 2 weeks of light warmup via a third-party warmup service connected to the SMTP credentials. The per-mailbox ceiling stays at 4 total/day (2 outbound + 2 warmup) — warmup cannot push you above that.
What about Outreach's CRM integration — does that still work with ColdRelay mailboxes?
Yes. Outreach's CRM sync (Salesforce, HubSpot, etc.) is independent of the mailbox infrastructure. As long as the mailbox is connected to Outreach, engagement data, sequence activity, and reply tracking flow to your CRM the same way they would with any other mailbox. CRM sync is the main reason teams choose Outreach over lighter cold-email tools — that benefit doesn't disappear when the underlying mailbox is ColdRelay.
Can I switch from Outreach to a different sending tool later without losing my ColdRelay setup?
Yes. ColdRelay mailboxes are standard M365 accounts with SMTP/IMAP and OAuth available. If you decide Outreach isn't the right fit (or you want to move cold-prospecting to a more purpose-built tool like Instantly or Smartlead), you can reconnect the same ColdRelay mailboxes to the new tool without re-provisioning. The infrastructure investment is portable.
What if my Outreach instance rejects ColdRelay's M365 tenant outright?
If your Outreach admin can't or won't allow external M365 tenants, the practical path is to use a different sending tool for cold-prospecting on the same ColdRelay infrastructure. Instantly, Smartlead, EmailBison, and Saleshandy all connect via SMTP/IMAP (no tenant trust required) and work with ColdRelay mailboxes out of the box. Outreach continues handling your warm-pipeline reps on corporate mailboxes. This dual-stack setup is actually what most enterprise teams end up running.