Softbounce Errors

Incident Report for SMTP2GO

Resolved

This incident has been resolved.

Posted Oct 15, 2026 - 17:23 UTC

Investigating

The team recently updated how our servers process traffic. Specifically, SMTP (https://www.rfc-editor.org/info/rfc5321/#section-2.3.8) requires 0x0d immediately before 0x0a; a recent patch to Exim against "SMTP smuggling" has altered its behavior when it encounters a missing 0x0d.

The team is looking into rolling back this update, but in the meantime, we are suggesting connecting to 45.33.50.34, 43.228.184.6, or 45.33.53.153 instead of the mail.smtp2go.com hostname as a potential workaround.

Posted Oct 15, 2026 - 15:03 UTC

This incident affected: Email sending (SMTP service).