Hi Martha. I’m not aware of any specifics why Theme My Login wouldn’t be playing nice with The Events Calendar, Pro, or its Community Events add-on.
Maybe it’s something simple like re-saving your Permalinks. If that doesn’t do it…
There could be quite a few things that would lead to a plugin or theme conflict. Would you mind enabling WP_DEBUG and WP_DEBUG_LOG (see previous link) and sharing any PHP errors you see while navigating your site’s home page, events page, single-event pages, and any other of your site’s pages relevant to this ticket (e.g. new account, login, Community Events form, etc).
Once you share your WP_DEBUG findings, we may be able to get an idea of any plugin or theme conflicts.
If any errors do appear while navigating your site’s pages, please copy and paste them in their entirety into a new ticket reply — along with the URL of where you saw the error(s) — and make sure you set it as a Private reply.
Let us know what you find. 🙂