Mailbox Blocked From Sending? Google and Microsoft Fixes

A Google Workspace user suspended for sending too many emails is blocked at the account level. So is a Microsoft 365 user placed on the Restricted entities list. Your own mail provider has stopped outbound mail from that one mailbox.

The way back is usually short. Copy the exact error and check the account for signs of compromise.

In most cases an admin can then restore it. For Workspace, that happens in the Google Admin console (restore a suspended user). For Microsoft 365, it happens on the Restricted entities page of the Microsoft Defender portal (Microsoft Learn, restore restricted users).

The exception is a Google suspension for abuse or a Terms of Service breach, which neither an admin nor Google support can reverse. Restoring is the easy half. The block comes back unless the mailbox starts sending differently.

Is it a provider block, a spam folder or a block list?

People say "my email is blocked" about three different problems:

• Provider block. Google or Microsoft refuses to send for you. The error or bounce comes from your own provider, and nothing leaves the mailbox.
• Spam folder. Mail arrives, then lands in junk. The causes are reputation, authentication or content.
• Block list. The receiving server rejects your mail because your domain or IP is listed somewhere.

This page covers the first one only.

How do Google Workspace and Microsoft 365 blocks differ?

Sources: Google Workspace sending limits and Microsoft's outbound spam overview.

What triggers a Google Workspace sending suspension?

A standard paid user can send 2,000 messages a day and reach 3,000 external recipients a day (Google Workspace Admin Help). Cross a limit and the user cannot send new mail for as long as a day. Google also warns that a user who keeps exceeding the limits might have the account suspended.

The restore page for suspended users names two cases an admin can reverse: a temporary restriction for exceeding account limits, and an automatic suspension for potential spam abuse.

An account suspended for abuse or a Terms of Service breach cannot be restored by an admin or by Google support, and Google's limits page warns that spam senders can lose sending for good.

For cold email, a mailbox anywhere near the 2,000 ceiling is proof the setup is wrong. The setup that breaks is one mailbox doing the work of twenty. As a rule, I count on contacting at least 10,000 people a month for 30 to 35 B2B sales calls, and that is a job for many mailboxes, never one.

My team gets volume by adding mailboxes and domains instead: that usually means 10 to 20 domains and 20 to 40 mailboxes, more for bigger companies.

What triggers a Microsoft 365 restricted sender?

Microsoft 365 checks outbound mail for spam and unusual sending activity, and its default outbound spam policy covers every sender in the tenant (Microsoft Learn, outbound spam policies). Microsoft reads outbound spam from a user as a sign that the account is probably compromised.

A user gets blocked by passing a spam threshold Microsoft does not publish, or by hitting an overall outbound message limit whatever the spam verdict. Microsoft's overview also says bulk email is not a supported use of Microsoft 365 and works only on a best-effort basis.

How do you restore sending today?

Work through this in order:

1. Copy the exact error with the time it appeared. The wording tells you whether you hit a limit, a suspension or a restriction.
2. Pause every sequence on that mailbox before the sending tool retries in the background.
3. Check for compromise. Review recent sign-ins and connected apps. Then reset the password and turn on MFA (a second sign-in step, such as a phone code), which Microsoft asks admins to do before an unblock.
4. Restore in the right place. Google: restore the user in the Admin console. Microsoft: Unblock on the Restricted entities page.
5. Give it time. Once an admin clicks Unblock, Microsoft says the restriction is usually gone within an hour and should take no longer than 24 hours. For limit errors on personal Gmail, Google says sending usually returns within 1 to 24 hours (Gmail Help).

What should you change before you send again?

After a block, the only goal is to avoid a second one. I never answer a block with new copy, because copy cannot rescue a weak sender or a bad list. One email, word for word, pulled 2% replies at one company and 7.5% at another. The sender behind it made the difference.

You can send 100,000 more emails today, next week or next month. Nothing changes until the sender is fixed.

• Separate domains. Cold email never shares the domain that handles your invoices.
• Authentication. I want SPF, DKIM and DMARC live on each domain we send from before the first email.
• Warm-up. I do not let a new mailbox near a prospect before 10 to 14 days of warm-up. Treat a mailbox restored after spam signals like a new one.
• Ramp. I raise volume only once that warm-up is finished.
• Verified lists and monitoring. Verify each contact before it enters a sequence, so the bounce rate stays below 0.5%. Check bounces, complaints and provider alerts weekly, per mailbox.

Sending works but replies died: a different problem

If the mailbox sends but the mail arrives badly, you are on a different layer:

• Mail lands in spam or replies dry up: check sender reputation every week.
• Receiving servers reject you and name a block list: read what to do if the domain itself is blacklisted.

What should founders ask their admin or agency?

Ask these before anyone touches the settings:

1. Which provider blocked us, and what was the exact error?
2. How many emails did this mailbox send per day last week, and was it still in warm-up?
3. Was MFA on, and were there sign-ins we did not expect?
4. What changed in the last 7 days: a new list, tool or mailbox, or higher volume?
5. Does this mailbox sit on our main company domain?

Then pick a path:

• Resume after a single limit block on a clean, warmed account. Before the restart, shift part of that mailbox's daily volume to other warmed mailboxes, so no single mailbox sits near the limit that tripped.
• Slow down after a second block in a month, or after restoring a Google spam-abuse suspension. Cut volume, warm the mailbox up again and re-verify the list.
• Rebuild when Google cannot restore the account, when cold volume runs through Microsoft 365, or when cold mail goes out from your main domain.

If you build it yourself, budget about a month before the first new message goes out, most of it spent buying domains and warming mailboxes. The full sending setup shows the build order. Or hand the rebuild to the senior people on our cold email agency team, who handle the domains, authentication, warm-up and monitoring.

Fix the sender first. Then scale.

If your Google Workspace or Microsoft 365 mailbox keeps getting blocked and you cannot tell whether to fix it or rebuild, book a call and I will help you decide.