Problems Buddypress

Hello,
I’ve a problem with the inscription of new members.
I’ve WordPress 4.82 et Buddypress 2.91 installes.
The problem is, when I push the “inscription” button, the form doesn’t appear. Il I’m deactivating the plugin, everything’s ok, but if the plugin is activated the form doesn’t appear. How can I do it working?
Thx for your answer

Greetings
Guido