I have the same problem with version 10.8.5 on WordPress 6.4.3 with PHP 8.2.16. When I went back to the dashboard it did install and I was able to activate it. It doesn’t seem to be working correctly, however. When I go to Settings>RSVPMaker four tabs appear with a “Loading” message and then the tabs disappear. When I try to add a new event I do not get the “RSVP / Event Option” popup so I can’t create any events.
