New Topic not working

This is the second time I’ve installed simple-press. the first time, on a different site, everything worked fine.
This time, it installed and I set up groups and forums, but the add topic button doesn’t work.

https://www.landslide-possiblefutures.com/land/forum/artist-forum/

I don’t have any social media plugins (or many plugins at all) installed.

Please help!

Thanks.