# Incoming email rejected by YunoHost
**URL:** https://forum.yunohost.org/t/incoming-email-rejected-by-yunohost/41506
**Category:** Support
**Tags:** email, english
**Created:** [February 8, 2026, 5:47pm UTC](https://forum.yunohost.org/t/incoming-email-rejected-by-yunohost/41506 "2026-02-08T17:47:30Z")
**Posts on this page:** 1
**Showing post:** 5
### Author:  [@djez](https://forum.yunohost.org/u/djez)
#### Post date: [February 9, 2026, 4:25pm UTC](https://forum.yunohost.org/t/incoming-email-rejected-by-yunohost/41506/5 "2026-02-09T16:25:34Z")
Good news: the alias is working! The error has changed, which means the first issue is resolved.
Now, the new error is different:
```auto
553 5.7.1 : Sender address rejected: not logged in
```
This happens because `tommi.space` is also a domain on your YunoHost server. When Proton Mail delivers an email from `surfing@tommi.space` to your server, Postfix sees the sender address belongs to a local domain but the connection is not authenticated — so it rejects it as a potential impersonation attempt.
This is caused by the `reject_sender_login_mismatch` directive in Postfix’s configuration.
You have two options:
1. **Quick test** : try sending your test email from an address that is _not_ on a domain hosted by your YunoHost (e.g. a Gmail address 🤮). That should go through fine and confirm the alias works.
2. **Permanent fix** : if you actually need to receive emails sent from `@tommi.space` via Proton Mail, you can comment out `reject_sender_login_mismatch` in `/etc/postfix/main.cf` and reload Postfix (`systemctl reload postfix`). SPF, DKIM and DMARC already protect against sender spoofing, so the security impact is minimal. Note that YunoHost may restore this line on `regen-conf postfix`, so keep that in mind.
This exact issue was discussed and solved here: [Question Postfix -- 553 5.7.1 ... : Sender address rejected: not logged in](https://forum.yunohost.org/t/question-postfix-553-5-7-1-sender-address-rejected-not-logged-in/34558)
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