Hi UEA,
Totally get how annoying that pop-up would be, especially when you're sending emails all the time. Normally, once that message pops up, clicking Add email and setting an email address should stop it from appearing again. If clicking Add email isn't doing anything though, that does sound like a bit of a software hiccup. A good first step is to try clearing your AccountRight cache, then jump back in and see if the option works as expected.
If it's still playing up after that, the best next move is to reach out to our live chat support through our virtual assistant, MOCA, or submit a case via My Account. The support team can take a closer look and help get it fixed properly.
Regards,
Sai