Webmail not working after password change

Issue :

Webmail for an email account stopped working after the password was changed. It said ‘password updated successfully’ but when trying to login again via webmail, following error occurred :
invalid username or password
Mail quota and disk space usage for the email account is fine.

Fix :

Try running the cPanel script — /scripts/fixpop
If that does not fix the issue then try recreating the email account itself.