550 5.7.60 SMTP; Client does not have permissions to send as this sender
550 5.7.60 SMTP; Client does not have permissions to send as this sender
Authentication succeeded. This is not the Basic auth shutdown. The From address in the message does not belong to the mailbox that authenticated, and Microsoft 365 will not let one send as the other without an explicit Send As permission. Common after pointing a device at a shared or service mailbox while leaving the old From address in its settings.
Check it from the machine that is failing
npx zerosmtp-check --explain "550 5.7.60 SMTP; Client does not have permissions to send as this sender"
No install and nothing sent. It reads the refusal your own client printed - which is rarely what the server said, because libraries and device panels rewrite it - and says which of these cases you are in.
If the send is hanging rather than being refused, the cause is usually the network and not the credentials. npx zerosmtp-check with no arguments checks ports 25, 587 and 465 from where you are standing.
This is not the Basic auth shutdown
Authentication worked. Do not change the authentication settings — the problem is the From address.
- Check what address the device or application puts in
From. - Check which mailbox the credentials belong to.
- If they differ, either set
Fromto the authenticated mailbox, or grant that mailbox Send As on the address you want to use.
This turns up most often after pointing a device at a shared or service mailbox and leaving the old From address in its settings.
Two things this is often confused with
| Symptom | Actual cause |
|---|---|
| Connection times out; no authentication error ever appears | The network is blocking outbound SMTP. Cloud providers block port 25 and often 587 by default — see troubleshooting. |
Certificate verify failed / unable to get local issuer certificate | The device’s trust store cannot validate the server certificate. Common on firmware predating current root CAs — see the Canon Maxify MB2755 case. |
Related
- All SMTP AUTH error messages
- Which devices have OAuth firmware
- What breaks at the end of December 2026
Seeing a string that is not here? Report it with what produced it. Errors from real hardware are worth more than anything transcribed from documentation.
Last reviewed 2026-08-16.
Updated 22 Aug 2026