Will Yardley writes:

yet the problem seemed to persist for more than an hour.

Also, how can I flush the cache for a non-default instance's cache using doveadm -- "doveadm auth cache flush" doesn't seem to have an '-a' option AFAICT.

If you only want to dump a few auth cache entries, you can just authenticate with a bad password. When a different (and possibly correct password) is supplied, there will be a cache miss and the new credentials will be cached.

echo "1 login someuser badpassword\n2 logout" | netcat --ssl your-imap-server:993

Joseph Tam <jtam.home@gmail.com>