As long as you're not trying to remove the Primary email ( if you are, you need to promote the other email to primary or add a new one) and the one you want to remove is not currently associated with any transactions, in theory, you should be able to remove it. As there's no way to look at your account setup via the public community you may need to contact customer service for assistance. Before doing that, try deleting your web browser's cookies, temp files, history, cache, etc., then close the browser, reopen it and log back into your account so you can try it again. If you get the same results, then perhaps phoning customer service for assistance would be your next step.
