Key takeaway: Smartlead connects to Frostmailer inboxes over IMAP and SMTP or OAuth. What matters is the configuration, not the clicking: daily limits, randomized delays, rotation across the full pool, a custom tracking domain, and IMAP set so replies come back.

Smartlead connects to your Frostmailer inboxes over IMAP and SMTP or OAuth. The mechanics are close to any sending platform. What matters is the configuration, not the clicking.

Step 1: Add email accounts

In Smartlead, open Email Accounts and add a new account. Google Workspace and Microsoft inboxes typically connect via OAuth. SMTP mailboxes are added with manual server credentials.

Step 2: Configure SMTP and IMAP

For manual connections, enter the SMTP host and port (sending) and the IMAP host and port (receiving replies). Configure both. An SMTP only setup will happily send campaigns while every reply disappears into a mailbox nobody is watching, a genuinely expensive mistake.

Step 3: Bulk upload

If you are connecting many inboxes, use the CSV bulk import rather than adding them individually. One row per inbox, credentials in columns. This is the difference between ten minutes and an afternoon.

Step 4: Turn on warm-up

Enable it per account and leave it running permanently, even on pre-warmed inboxes. It keeps the engagement signal alive between campaigns and cushions a bad week.

Step 5: Set sending limits and rotation

Cap each inbox to a conservative, provider specific number: 2 to 3 a day on Azure, up to 15 a day on Google. Smartlead's strength is rotating sends across many connected inboxes. Configure the rotation so a single campaign spreads across your whole pool rather than hammering a few accounts. Add randomized delays between sends.

Step 6: Add your custom tracking domain

Point a CNAME subdomain you own at Smartlead and set it as your tracking domain, so your links do not route through a shared domain whose reputation you do not control. Or skip open tracking and measure on replies.

Step 7: Seed test

Send to test inboxes across Gmail and Outlook. Verify delivery, check actual placement, and confirm a reply lands in the master inbox. Then launch.

Step 8: Watch the first week closely

New infrastructure plus a new campaign is the moment problems surface. Track bounce rate (should be under 2 percent) and reply rate daily. If bounces spike, stop and verify your list before sending another batch. Do not push through it.

The settings that matter most: daily limits, randomized delays, rotation across the full inbox pool, a custom tracking domain, and IMAP configured so replies come back. Everything else is preference. Frostmailer inboxes arrive ready to plug into Smartlead with credentials and tracking already set.

Want this done for you?

Our Build and Release service stands up your entire cold email infrastructure: domains, mailboxes, authentication, warm-up, and tracking, all authenticated and ready to send. You skip the weeks of setup and start with campaigns.

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