Follow the following steps to reset the postfixadmin password:

  1. Get the Encrypted Version of the string that you want to set as password :

dovecot -s MD5-CRYPT -p | sed ‘s/{MD5-CRYPT}//’

  1. Copy the output

  2. Login to Mysql database

  3. Use database Vmail or whatever in your case.

5.Run the following query :

update admin set password='’ where username = ‘