Thanks, Dale! Got it and I was able log in.
I went in and was able to activate both plugins normally without any issues. If you log in now, you’ll see both plugins activated and functional using the latest versions.
Since we were unable to replicate the issue on a clean test site, that leads me to believe that there is something conflicting on the live site. Whether that conflict is due to the installed theme or one of the other plugins, it’s really tough to tell, but the signs certainly seem to be pointing in that direction.
If you’re interesting in pinpointing the conflict, I would suggest installing and activating your theme and other plugins one-by-one on the test site. We know now that The Events Calendar and The Events Calendar PRO are both working without conflicts on the test site, so it’s a matter of slowly recreating the live production site on the test site to see where the conflict arises.
Sorry I don’t have a concrete solution for you here, but hopefully this helps shed some light on what’s happening and provides some more direction on getting to the bottom of it.
Cheers!
Geoff