Resolved after 2 hours 20 minutes, affecting Email sending (SMTP service), on October 15, 2026.
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.
Affected components
Update timeline
- investigating Oct 15, 2026, 03:03 PM UTC
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.
- resolved Oct 15, 2026, 05:23 PM UTC
This incident has been resolved.
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