Problem SMTP configuration VTENEXT

Good morning community,
I am writing to you as we have just set up the VTENEXT platform for internal use.
We are experiencing a problem with the smtp configuration. Whichever email provider we enter, the system replies as follows: "The email cannot be sent to the administrator. Please check the configurations of the mail server and the administrator`s email".
The parameters as suggested in the manual are entered correctly.
The main requirement is that it works with the provider Aruba.
I attach below the test images with both Aruba and Google accounts.
Could you help us solve the problem?
Thank you in advance,

Ciao, non ho mai provato con Aruba. Con Gmail devi utilizzare le password delle applicazioni non puoi usare la normale pw

Hello,
I experienced the same issue at the beginning, but I also had same problem with other web apps (all based, for mail sending, on PHPMailer engine).
The trick is, if your SMTP server requires connection on port 465 (as I can see in the screenshot) and with SSL encryption, to type "ssl://" in front of the server address.
In this case: ssl://smtps.aruba.it .

You can see, in your other screenshot (Gmail case), the server address has been automatically filled with "ssl://" prefix ... :-)

Please try and let us know.
Regards!