As I can see this is a common problem. I have the same.
Having some computers in my account for some years, now I can't add neither new one nor smartphone because of trusted device confirmation email never arrives.
I waited for about a month, repeating from time to time.
As it pretty common problem, could Teamviwer fix it finally?
I have no "spam" folder, letters just never arrive.
For some reason I can't use two-factor auth, thanks in advance for any else suggestion