I was having some trouble with an unresponsive campaign creation button, and I have also read of others facing various issues with the PopAds interface(payment and other unresponsive buttons/actions).
I tried dozens of things, but after doing some sleuthing I found that using a 4G connection solves most simple issues people experience with PopAds.
I have a hunch as to why that works, but haven't looked into it. If anyone has a definitive answer, I would love to know.