Description: Here we solve the error related to squirrel-mail client and Postfix server. The error we was facing ERROR: Message not send Server Replied Transaction Failed 5188.8.131.52 <email>: Relay Access Denied.
We try to resolve the issue and finally we got the solution of this error.
First thing you need to check the hostname of your system.
For this you need give the command:
Than you need to open the file in your favorite editor we use vim: