Thunkable Live not working on iOS 13.4.1?

Hi, Thunkable Live doesn’t allow login, there’s no interface for logging in. When I use wifi or 4G and I restore my iphone but I can’t see the sign in button.
Please help!

Maybe the wifi is not good. I find that when the wifi is bad i can’t see the sign in button.

When I use 4G. I can’t see the sign in button too.