I have found an issue with the email registration process in the Tapo app in IOS. When you start typing your email for registration purposes, the textbox will automatically capitalize the first letter of your email address on IOS phones, like this: John.smith.fake@gmail.com instead of john.smith.fake@gmail.com. (I don't know about Android, have not tried.)
Email addresses are supposed to be case-insensitive, still somehow this email address gets stored in a case-sensitive way in one or more of Tapo's databases. This leads to an awkward situation that when the app tries to validate certain functions it will try using an all-lowercase email address, and compare it with the database using a case-sensitive compare, and these functions will fail. Changing "Doorbell Video Call" is not possible when this happens, and in general the app keeps reminding the user that there are problems with his network. Even if the user uses perfect wifi signal.

As soon as I re-registered using an all-lowercase email address (by explicitly switching to lowercase in the app, because it always wants to start with upper case), all these problems suddenly went away.

I think this is a simple to fix bug, and would save a lot of headaches for the users, and probably get rid of lots of support messages.