Neomail shows no messages even though I can see them through pop and imap.
This is rare but has occured in the past. Normally this is due to neomail’s db files becoming corrupt. Make a backup and remove the .db files in /home/username/.neomail-account/username/
Replace ‘username’ with the main account’s username and ‘account’ with the first part of the email address. Once completed relog into webmail.