new subscriber password

Hello,
When I create a new subscriber, the message received by the subscriber does not include any password indication.
There is only one link that leads on a page to reset the password !
If the subscriber clicks on the reset, the password proposed on the screen (which is not the one generated at the subscriber’s creation) disappears, and a new login screen is then presented.
Forcibly, it is then impossible for the subscriber to connect because it has not received at any time the password, including in the mail informing him of the reset.
According to a technician of the hosting platform of the site, it would be a problem of strength of the password. This seems unlikely since the generated passwords are described as strong, like that : “LnYwAQ6O5I&$RCey”.
The host considers that the problem is related to WordPress (in my case, version 5.3)