I have a serious issue where customers are not allowed to check out because its not liking their email address. I used to get 1-2 reports a month about it, and I figured user error, like they typo'd .com or used a ,com (comma) or an invalid symbol in their email address.
I am now getting at least 1 report a week about it - it's getting worse. I finally got a customer to screenshot it for me (see attached) and it is very obvious they are using a valid email address.
I am using CE 1.9.2.3
Thank you.