I have checked the URL and it seems your are using phpBB forum Kindly check for the following configuration in your admin panel of forum:
Admin CP>general admin>configuration and enable the smtp mailer with these settings
Servername = mail.pspbetapsi.com
Userneme =
youremail@pspbetapsi.com
password = correctpassword
Change username and password with the correct *working* email address. You should able to send receive with these email address using webmail/outlook.
I dont think that there is anything need to do with server as there are many other domains also which are using phpBB forum smoothly.
Please check it from your end.