Domoticz

Since about 6 months I have a iPad Air with IOS 12.4.9. I am configuring Dashticz for this iPad to mount him on the wall. Since one week I found out that the Dashticz buttons on this iPad are not reacting anymore, not one! Before everything worked!
I used Safari, Chrome, Dolfin, they all don't react on pushing a button while another iPad, iPhone and PC are working fine. The Dashticz gui is ok, everything is showing.
Empty cache in the browsers is not solving the problem
Are more of you having this problem lately?

Domoticz 2020.2 (12393)
Dashticz V3.7.3 beta
dzVents 3.0.12
Python 3.7.3
PHP 7.4.12

Nobody?

Have you tried with basic settings? A config.js with only changed IP address and port.

Just found out that when I take a CONFIG.js from a month ago it works fine so I think I have to compare these. Are there any settings which could cause this behaviour?