dovecot - May 2020 - Dovecot v2.3.4.1 Debian 10.3 mbox format - Error: chdir(/var/spool/mail/domain/user) failed: Not a directory

Hi colleagues,


I am trying to setup dovecot and have a strange problem. I configured it to:

 #dovecot -n|grep ^mail
 mail_gid = mail
 mail_location =
mbox:/var/spool/mail/%d/mailboxes/%n:INBOX=/var/spool/mail/%d/%n
 mail_uid = mail

And also setup exim4 to use it. I sent a test message and observe a mailbox file
/var/spool/mail/domain/user, containing this message. But when I try to access
dovecot with a client (thunderbird), client cannot fetch mail, and I observe
error in the dovecot's log:

May 09 23:35:51 imap(user at domain)<25179><JNFIDz2ldeOsEAE3>:
Error: chdir(/var/spool/mail/domain/user) failed: Not a directory

What is it, and how to solve it? Thank you.

Kind regards,
Viktor