Class "GApp3" not found

after the migration of joomla (to 4) and the reinstallation of modals (12.4.0 pro) it is not possible to use the regular labs modals button in a article. the following error message appears: Class "GApp3" not found
i logged into my account and searched for this message in the forum. there is an article about it, when i call it up, the following error message appears:
You do not have permissions to access this page.

Why am I not authorised and how can I solve the problem?

regards,
Vreni

thank you

I am looking for a solution to another problem, but when i try to view a post in the forum, the following error message appears:
You do not have permissions to access this page.

Why am I not authorised?

regards,
Vreni

for some requests it works for others not