Cannot add verification email, "Changing email too fast", "Username contains invalid characters"

I cannot add a verification email as I keep getting the message “You are changing your email too fast, try again later” or “Your username contains invalid characters”. I am not even trying to change my email, I am trying to add one for verification. My email contains only letters so how are they invalid? The only reason I am trying to verify this account is to delete my phone number from it. This is astoundingly horrible design.