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SOLVED imap connections limted to 10 makes clients fail to connect

  • After I moved my mail-server to cloudron, I experienced regular erros on my thunderbird, saying the server rejected my login.
    It was not updating the IMAP-folders and the only way to read my emails, was through K-9.
    in a quiet moment, I installed KDEPIM and Kontact provided me with a more helpful err-msg.

    in German:

    Anmeldung fehlgeschlagen, die Serverantwort lautet:
    A000002 NO Maximum number of connections from user+IP exeeded (mail_max_userip_connections=10) [ UNAVAILABLE ]

    I do have 2 accounts configured in my mail-client, with a lot of IMAP-folders and never experienced a pbl. with other mail-servers I used so far.

    ClientSystem: Debian buster,
    KDE 5.54
    thunderbird: 60.5.1-1
    kdepim: 4:17.12.3+5.102
    kontact: 4:18.08.3-1


  • Staff

    @chymian It seems it's hitting the rate limit. Can you try this:

    docker exec -ti mail /bin/bash

    edit /run/dovecot/dovecot.conf. add something like this:

    protocol imap {
      mail_max_userip_connections = 50

    Then (inside the container)

    supervisorctl restart dovecot

    Note that the above setting will not persist server reboot. If the above works, we can get it fixed in the coming update.

  • from a quick test, it seems to work with a limit set to 50
    TB works, even with sieve editor open.
    if I don't report otherwise within a week, it is a working solution.

    thx johannes

  • Staff

    OK, I have fixed the code as well, so it will part of next update (3.6). Until then please update file.