At-times users may run into a situation where some local ISP’s may deny services to be run over port 25 (which is the default port for SMTP) for certain reasons – usually due to security purposes. In that case server administrators configure and enable the alternative SMTP port on a server, which the end user can use as an alternative SMTP port in email account setups on their local PCs.
Following are the steps to add alternative SMTP ports via. WHM/cPanel
Step 1 : Login to WHM
Step 2 : Click on Service Configuration.
Step 3 : Select “Service Manager“.
Step 4 : You can open additional port along with the default port 25.
If you need any help with this, please feel free to contact our support department, we’d be glad to assist.