Resolve paused mailboxes, stalled sequences, import rejections, verification failures, and an exhausted cold-send meter
A Mailbox Is Paused
Find the cause, then resume.
The Mailboxes tab shows why a mailbox paused. Match the reason to the fix:
Bounce rate over 2% — clean or re-verify the list slice that bounced, then resume. Sending to verified leads only keeps the rate down.
Rate limited — the provider throttled the mailbox. Laureo backs off and resumes automatically; no action needed.
Token expired — an admin reconnects the mailbox to refresh the OAuth connection.
Preflight regression — a DNS record stopped resolving. Re-check domain setup, fix the record, re-run the preflight, then resume.
Replies keep flowing while paused
A paused mailbox only holds new cold steps. Replies from prospects still arrive in your inbox, and you can still answer them.
Provider Rejection Codes
What common SMTP status codes mean, and the fix for each.
When a provider rejects or defers a send, it returns an enhanced status code. The Mailboxes tab and the health strip translate the code into plain language and a fix. Codes that start with 4 are temporary and usually clear on their own; codes that start with 5 are permanent and need a fix before sends succeed.
4.7.23 / 4.7.26 / 4.7.27: authentication deferrals. Your domain’s SPF or DKIM did not pass or align. Check your records in Settings, Outreach, then re-run the domain preflight.
4.7.28: the provider is temporarily rate-limiting your domain. This clears as sends slow down. Keep lists clean and let the managed ramp pace the volume.
5.7.26 / 5.7.515: permanent authentication failures. SPF or DKIM does not align with your sending domain, or the mailbox does not meet the provider’s sender-authentication requirements. Fix SPF, DKIM, and DMARC in Settings, Outreach, then resume.
5.7.1: the receiving server blocked the message for policy reasons. Review the content for spam triggers and confirm authentication passes, then resume.
5.1.8 / 5.7.708 / 5.7.750: your email tenant restricted the sending address or blocked the domain. Resolve it with your email admin before resuming.
5.1.1 / 5.4.1: the recipient address does not exist or was rejected. This is a bad address, not a mailbox problem. The lead is suppressed automatically.
4.2.2 / 5.2.2: the recipient’s mailbox is full. This is on the recipient’s side, so no mailbox action is needed.
Unknown codes fall back gracefully
If a rejection carries no recognized code, the mailbox still shows its plain pause reason, such as high bounce rate or sending limit reached. You never lose the reason, you just get a sharper one when the provider gives us a code to read.
A Sequence Is Not Sending
Common reasons a launched sequence sits quiet.
Daily limit reached — every mailbox hit its per-mailbox daily limit. Sends resume tomorrow, or connect another mailbox to add pool capacity.
Outside the send window — leads are in timezones where it is currently outside business hours. Sends resume when their window opens.
Leads suppressed — the remaining leads are on your suppression list and were skipped. Import fresh, verified leads.
No active mailbox — the sequence depends on a mailbox that is paused or disconnected. Resolve the mailbox or add another.
Import Rejections
Why some rows did not import.
After an import, Laureo reports how many rows were imported and how many were skipped, with reasons: duplicate addresses, matches to existing customers, suppressed addresses, do-not-contact entries, or malformed rows. These skips are protections, not errors — review the reasons, fix any genuinely bad rows in your file, and re-import. If the whole import was rejected, the most common cause is a missing list-source attestation.
Verification Failures
Leads stuck as risky or invalid.
Leads marked invalidfailed email verification and will not be sent — remove or correct them. Leads marked risky (often catch-all domains) are uncertain; enrolling them raises bounce risk, so review before adding them to a sequence. If a large share of an import comes back risky or invalid, the list source is likely low quality.
The Cold-Send Meter Is Exhausted
What happens when you reach your monthly cold-send volume.
Cold sends are counted against an enforced monthly ceiling per user (about 7,500 cold emails per month on Ultra). This is a hard ceiling — unlike the warn-only campaigns meter, the cold-send meter stops new cold sends once you reach it. When it is exhausted, in-flight sequences defer their remaining sends to the next monthly reset, you get a single notification, and a launch attempt is blocked on the meter gate.
Replies always send, even at the ceiling
Reaching the monthly cold-send ceiling never stops you from replying to prospects who already answered. Cold replies in your inbox are never counted against the meter, so the conversations that matter most keep moving.
Where Notifications Appear
How Laureo tells you something needs attention.
Cold Outreach posts to your normal notifications — a mailbox auto-pause, an exhausted meter, or a sequence blocked at launch all surface in the notifications inbox (and to org admins for mailbox-health events). Keep an eye on the bell so a paused mailbox does not quietly stall a sequence. See Notifications Inbox.