Email notifications nothing happens

Good morning,
I have a server that virtualizes an Ubuntu 18.04.4 LTS container.
In the container I have a pro seafile and two CE seafile suitably modified to use 3 different users for the services, 3 database users, 3 databases, everything works wonders if it were not that in an CE installation I have to enable email notifications but despite following the guide, he doesn’t works.
The version of the seafile in which I am configuring is 7.0.5
this is my seahub_settings.py

-- coding: utf-8 --

SECRET_KEY = “****************”
DATABASES = {


}
CACHES = {


}
EMAIL_USE_SSL = False
EMAIL_USE_TLS = True
EMAIL_HOST = ‘smtps.aruba.it’ # smpt server
EMAIL_HOST_USER = ‘noreply@**.’ # username and domain
EMAIL_HOST_PASSWORD = ‘**********’ # password
EMAIL_PORT = 465
DEFAULT_FROM_EMAIL = EMAIL_HOST_USER
SERVER_EMAIL = EMAIL_HOST_USER

In the past I had to create this symbolic link:
ln -sfn /usr/lib/x86_64-linux-gnu/sasl2/ /usr/lib64/sasl2
because I had an error:
looking for plugins in ‘/usr/lib64/sasl2’, failed to open directory, error: No such file or directory

The machine logs have no noteworthy details and the seahub logs do not give me any information, when a notification should start simply nothing happens.

Tips?