Cerberus FTP Server: OAuth 2.0 and Microsoft 365 SMTP AUTH
Status: Check vendor advisory
The vendor publishes a per-model list and revises it over time, so it is not copied here; a stale second copy of a moving list is exactly how somebody ends up acting on the wrong row. Check your exact model against the vendor’s own page.
What the vendor says
Vendor support article covers the exact 535 5.7.139 failure.
Read the vendor’s statement in full
Everything on this page comes from that document. If it and this page disagree, the vendor is right and this page is out of date — say so.
What to do instead
Once firmware is ruled out, three options remain, and they differ more than they look:
- Direct Send — free, but only delivers to recipients inside your own tenant, and needs a connector plus a static IP.
- A relay that still accepts a username and password — works for any recipient, and is three fields on the device rather than a project.
- Replace the device — sometimes the honest answer. A 2016 MFP with no OAuth path and no security updates is a hardware decision, not a mail one.
The migration guide walks through all of them, including Graph API and paid relays, and the quiz on that page gives a recommendation you can link to.
ZeroSMTP is the second option. It is free with no paid tier, accepts plain SMTP AUTH, and is capped at 200 messages a day — and it sends from a shared @msgwing.com address, not your own domain. If the from-address has to be yours, it is the wrong answer and the migration guide covers the others.
Create a free account · what to put in the device’s SMTP fields · the code examples
Related
- What the error message means — if the Cerberus device is reporting a code rather than a sentence
- The full compatibility list — every vendor, in one table
- Setup by printer brand — where the SMTP fields actually live in each vendor’s interface
Last reviewed 2026-08-16. Source: data/devices.json.
Updated 16 Aug 2026