[NSFW] Bugs? How to solve this?

I have used Events Calender for a while now, no problems have gotten back to me from visitors. Since a few weeks I keep recieving messages that made changes (I have added new events and deleted some) weren’t visable and that they can’t skip to next month in the month view.

I have checked it myself and one my Samsung S9 and on my laptop it is working fine, on my S7 it isn’t and I experience teh same problems as my visitors and on my tablet as well. All using Chrome and Samsung internet.

I have updated my Theme, WordPress and the plugin. I’m not technical at all and don’t know what else to do to fix this. Hope someone can help me.

My website is http://www.mistress-eve.com/agenda

The page I need help with: [log in to see the link]