w3services_net
The 25 port that is prompted here is actually 25 ports that your server cannot access other servers.
For example, when your mail server needs to send mail to the Google mail server, your mail server needs to communicate with the 25 port of the Google mail server. If your server cannot access Google's port 25, it will fail to send.
The default connection port is 25, I did not find the document mentioned can modify this default connection port, if you can find, I will optimize as soon as possible, thank you