Hey @ReD as @Duffman mentioned the healthcheck will be great here to know for sure what is happening.
Based on what you’ve described for symptoms and when it started my guess is that your server is still on version 2 and that is no longer compatible with the browser extension since version 4 was released in May of this year.
To take care of this you’ll need to update the version of your passbolt on the server and depending on which distribution the server is on you may need to upgrade your server. For example if it is an older version of Debian it won’t have the version of php that passbolt version 4 requires