trying entering a Mail Adress gives a error message

When I try to enter a correct email address on chess.com it gives me an error message claiming that I can change my mail address only three times a day - actually I can’t enter it even once

I had kinda the same issue when I tried to change my e-mail address it said it would send me an email but it never did. You should ask support

If you created your account through a third party sign-in, I don't think you can add an email. You'll need to contact Support directly using the option in the menu to assist

Thanks for the hint.
I contacted the Support, but I did not get any reply
I did create a chess.com account actually with an Apple account. Problem is that the support on this side it’s really not up to the quality of the product, which is indeed excellent.
This is actually the only reason I don’t book a diamond amount upgrade as I cannot be sure that on rainy days I will get the helping hand

Actually I was contacted by someone from support by mail offering me help. Let’s see how it pans out. 

DukeNabur from chess.com has resolved the / my problem in a nice and professional way - good to see that there are some helpful folks over there.