Hi,

we have one user using the old Alpine client with IMAP. Time to time (3 times per day or 3 times per week) he get error: "MAIL FOLDER INBOX CLOSED DUE TO ACCESS ERROR" and he complains, that inbox stops to refresh with new emails.

I don't know Alpine but I can imagine, that Alpine creates TCP connection to IMAPS and uses IDLE. I read wiki page about Timeouts [1] and it seems OK. Alpine is connected 5 or more hours without interrupt. But I found 'Connection closed' at approximate times of user reports in mail.log.

Am'I undestand it correctly, that 'Connection closed' is some kind of incorrect connection end? I can find 'Logged out' messages which seems to me as correct ones.

I can imagine that such situations may happend for moving clients, such a smartphone with losing signal. But mentioned user is on local network connected by cable.

I'm interested, what exactly 'Connection closed' in mail log means. We have following lines in log:

dovecot: imap(username): Connection closed in=63 out=288442

dovecot: imap(username): Connection closed (IDLE running for 0.001 + waiting input for 0.001 secs, 2 B in + 10+0 B out, state=wait-input) in=9668 out=17375

imap(username): Connection closed: read(size=3751) failed: Connection reset by peer in=4441 out=51431

dovecot: imap(username): Connection closed (UID fetch running for 0.008

• waiting input for 0.001 secs, 0.001 in locks, 101 B in + 202+202 B out, state=wait-input) in=3330 out=436043

Could it be problem in our network or Dovecot configuration issue? Can I somehow debug all connections for single client?

Thank you, Milo

[1] https://wiki.dovecot.org/Timeouts