Unable to execute POP3 command - but only on certain devices

Hi there,
this is my first post here and I hope not to violate guidelines…
Since 08/09.01.2024 I cannot receive E-Mails on my mobile phone with K9.
Error message when reactivating “Incoming mail server” is “Unable to execute POP3 command” and “Connecting to Server not possible”.

  • This error only occurs for receiving messages, sending works well.
  • Error occurs for provider “All-Inkl” (for my yahoo-acount everthing works still fine - also using POP3).
  • On my PC receiving All-Inkl Mails still works fine.
    -The error simultaneously occurred on two mobile phones of type “moto g10 (XT2127-2)” with Android 11, but it still works for another Android “moto g8 power lite” with Android 10.
  • Reinstalling K9 doesn’t help - error is reproducible (using latest version of K9 of cause).

My conclusion is that the issue must be related to K9 and Android11, because the error occurred simultaneously on two equal devices (but not on a different one) while everything still works fine on PC (using opensuse ClawsMail 4.2.0 with pop3).

It seems this is not a new issue, however last entries in this forum for this topic seem to be pretty old.

I really would like to keep K9… can anybody help?

Update: Error occurs with two different K9-versions: newest and 6.603 which was released before 08.01.2024.

Have you set up the account properly? If you use your own domain, you will receive a certificate error, and K-9 won’t connect to a server with a self-signed certificate or one issued to a different host. you must use the w0123456.kasserver.com as provided in your KAS setup. Only kasserver.com will return a valid certificate issued for the correct host.

Thanks for your helpful answer!
Well, the problem occurred suddenly with a well working setup (for years). So I guessed, it shouldn’t be a miss-configuration.
However, the certificates finally are causing the problem! For v6.603 I could (up to 08.01.2024) “accept the risk” of invalid certificates (shame on me!). This doesn’t work on v6.603 since 08.01.2024 for moto G10 (Android 11) because the pop up for accepting this risk doesn’t appear anymore. This still works with v6.603 on moto g8 (Android 10)… and it works again on v6.714 (from github) on moto g10.
However, I will care about valid certificates now!!
Thanks and regards

Please mark the solution so that other users can see that the issue is resolved when searching the forum.

1 Like