When a campaign send is marked Failed, BrandJet attempted to deliver the message but the sending provider or the recipient server returned an error. Here is how to read those errors and fix the most common ones.
Where to see the failure reason
Open the affected campaign, switch to the Activity log, and click a failed row. The expanded panel shows:
The sending inbox we used
The full SMTP response or provider error message
The timestamp and the lead email
This is the source of truth — start here, then map the error to one of the patterns below.
5.7.x — message blocked at delivery
The receiving server rejected the message because of reputation or auth failure. Look at the specific subcode:
5.7.1 Blocked / Spam — domain reputation low, content flagged, or DMARC failure. Improve warmup, check SPF/DKIM/DMARC, and reduce volume.
5.7.26 SPF / DKIM not aligned — your authentication records are missing or misaligned. See the DNS records article.
5.7.0 too many recipients — your provider rate-limited you. Lower the daily limit on the inbox.
5.1.x or 5.4.x — recipient cannot be reached
The destination address is invalid or unreachable. These are not a problem with your inbox.
5.1.1 / 5.4.1 mailbox not found — the lead address does not exist. Re-enrich or remove the lead.
5.4.7 message expired — the receiving server kept retrying and gave up. Often a temporary outage on the receiver. Safe to retry.
4.x.x — temporary failures
BrandJet retries 4.x.x automatically for up to 24 hours before marking the message permanently failed. You usually only see these as Pending followed by Sent in the log because retries succeed silently. If they stick around, the receiving server is genuinely throttling you — slow down.
OAuth revoked or token expired
The sending inbox OAuth token is no longer valid. Common causes:
You or an admin removed BrandJet from the provider connected apps list.
You changed your provider password and 2-step verification revoked old tokens.
The provider mailbox is suspended.
Fix: open Accounts → Email, click the inbox, and choose Reconnect. The campaign will pick up the new token on the next cycle.
Daily limit reached
The inbox already sent its allowed quota for the day. Either:
Wait for the next sending window (usually the next day in your timezone).
Raise the inbox daily limit if warmup health is green.
Add more inboxes to the campaign so the rotation has more headroom.
Sending account disconnected
The inbox we tried to use is no longer attached to the campaign. See the article on the Deleted account status for the full fix.
Unable to launch campaign
This appears at campaign start, before any sends, when the campaign cannot pick any inbox to send from. Common causes:
All sending inboxes are unhealthy (warmup paused, daily limit reached, OAuth revoked).
None of the inboxes match the channel (for example you only have LinkedIn accounts in an email-only campaign).
Google Workspace tenant requires admin consent that has not been granted.
Open the campaign settings and verify at least one healthy inbox is attached.
When to open a ticket
If the SMTP response looks generic (just 550 Failed) and none of the patterns match, send us the campaign name, the failed timestamp, and the inbox. We can pull the upstream provider logs and tell you exactly which check failed.