Email setup doesn't work

Install/Maintain/Configure
1

Hi, I’ll go straight to the point.
My app.ini looks like this:

ENABLED        = true
FROM           = notificatore@example.it
MAILER_TYPE    = smtp
HOST           = example.it:587
IS_TLS_ENABLED = true
USER           = notificatore.example
PASSWD         = *****

And:

ENABLE_NOTIFY_MAIL = true

The problem is that this doesn’t work. When I try to send a test email, it return the following error: first record does not look like a TLS handshake.

I also tried with:

HOST           = example.it:465
IS_TLS_ENABLED = false

And with:

HOST           = example.it:465
IS_TLS_ENABLED = true

None of this works. The weird thing is that I use the same exact configuration in PHP and emails are sent without any problems. Why all of this doens’t work on Gitea? Is there something I’m missing? I tried searching online but nothing has been able to help me (unsurprisingly so, since, like I said, the configuration is correct). Can anyone help me? Thanks in advance!

Note: English is not my mother tongue. Forgive me if I’ve made some mistakes.