Hello Yiannakis,

WebSite X5 Pro includes a built-in online control panel which can help you diagnose the cause of such a problem:

https://help.websitex5.com/en/v2019.1/pro/index.html?imp_pannello_controllo.htm

https://help.websitex5.com/en/v2019.1/pro/index.html?pannello_controllo.htm

Please follow the instructions in the links above, and run the email tests in the Website Test Section of the control panel.

You can of course revert to us once you have done so, should you need further help and assistance.

Kind regards,

Paul

https://webx5.pro