<![CDATA[Problems with sending mail]]>Hi, some of my Discourse Mail recipients do not get their mails (using cloudron mail, all status "green"), Just checked the events an found lots of these errors with different mail addresses. Any idea?

"message": "Upstream error: 450 4.7.25 Service unavailable, sending IPv6 address [xx:xx:........ must have reverse DNS record (S820)

edit: seems like this only happens, when the receiver uses Outlook/MS365 Mail ?! That possible?

]]>https://forum.cloudron.io/topic/13145/problems-with-sending-mailRSS for NodeFri, 16 Oct 2026 08:25:28 GMTSun, 19 Jan 2025 08:58:57 GMT60<![CDATA[Reply to Problems with sending mail on Mon, 20 Jan 2025 07:40:30 GMT]]>working now. thx 🙂

]]>https://forum.cloudron.io/post/100230https://forum.cloudron.io/post/100230Mon, 20 Jan 2025 07:40:30 GMT<![CDATA[Reply to Problems with sending mail on Sun, 19 Jan 2025 10:46:00 GMT]]>@sponch said in Problems with sending mail:

edit: seems like this only happens, when the receiver uses Outlook/MS365 Mail ?! That possible?

Yeah, I had the same problem.

@sponch said in Problems with sending mail:

guess I found the problem.
I had only configured IPV4 PTR and not V6 with my cloudron mail URL

That fixed it for me.

Although I also did this too

  1. in Network: under IPv6 section I chose Public IP (was previously Disabled)
  2. in Domains -> hit Sync DNS (for good measure)

Perhaps they were all needed.

If that still doesn't work look for more clues here https://forum.cloudron.io/topic/13122/email-sending-broken-after-updating-to-8-2-x-due-to-ipv6-issues/

]]>https://forum.cloudron.io/post/100196https://forum.cloudron.io/post/100196Sun, 19 Jan 2025 10:46:00 GMT<![CDATA[Reply to Problems with sending mail on Sun, 19 Jan 2025 10:21:59 GMT]]>mh..... still get the same error...
PTR setting Hetzner:
CleanShot 2025-01-19 at 11.21.13.png

]]>https://forum.cloudron.io/post/100194https://forum.cloudron.io/post/100194Sun, 19 Jan 2025 10:21:59 GMT<![CDATA[Reply to Problems with sending mail on Sun, 19 Jan 2025 09:48:07 GMT]]>guess I found the problem.
I had only configured IPV4 PTR and not V6 with my cloudron mail URL

]]>https://forum.cloudron.io/post/100191https://forum.cloudron.io/post/100191Sun, 19 Jan 2025 09:48:07 GMT