Email Address Is Not Invalid. I'm Muriel Mae Day.

I just registered.  It didn't go through because you said my email is invalid.  [email protected] is a valid email.  Frontier (ISP) says it is valid.  I could send you an email from that address so you will believe me.  I've used [email protected] for years.  Then last year, we were transitioned over to Frontier. Ever since then, I am having trouble with my email address.  Even though Frontier says it is valid, I asked them why they don't fix it.  I'm getting frustrated about these rejections.  Maybe you can help me with this problem instead of the one that I was going to post. Sincerely, Muriel Mae Day   PS:  My original post was about Facebook, but since you rejected my email address, I'm changing my question to, "why is a valid email address always showing up as invalid."   I can't put Frontier Communications down, because you don't list Internet Service Providers.  I think their service is bad.  And in order to get better service, which I should already be getting with the $84.00 I pay every month, they are asking for more money.  I don't think that is right?  [email protected] is valid, and Frontier knows that it is.  They just aren't doing anything about it.   I guess when I got rejected this time, I decided to rebel.  Sorry it had to be you as the final straw that broke the camel's back, but then you are a "help" company. Maybe the timing is perfect.  I'll get back to Facebook later.  I got here by googling.