IMAP connections closed when reading email with Outlook

Hello, Server users have reported problems connecting with Outlook to my email server and while checking the /var/log/maillog file I noticed several error messages like the following Jan 20 14:49:57 s2 dovecot: imap(prueba@domain.xx)<17360>: Connection closed (IDLE running for 0.001 + waiting input for 0.002 secs, 2 B in + 10 B out, state=wait-input) in=11, out=434, bytes=11/434 Jan 20 14:54:35 s2 dovecot: imap(prueba@domain.xx)<28167>: Connection closed (IDLE running for 0.001 + waiting input for 0.001 secs, 2 B in + 10+10 B out, state=wait-input) in=11, out=434, bytes=11/434
I noticed a similar behaviour with the pop3 protocol but no error message is reported in the EXIM log files