On Tue, Dec 10, 2019 at 8:51 AM Bottiger <bottiger10@gmail.com> wrote:

I sent an email to noc at gtt.net from 2 different emails and both got a reply saying:

5.1.0 - Unknown address error 550-'5.4.1 Recipient address rejected: Access denied [HE1EUR01FT058.eop-EUR01.prod.protection.outlook.com]'

Not sure if this means if they are blocking my email or if their email is broken.

Are you a GTT customer? If so, then I suspect the email you're looking for is inoc@ not noc@ ? The response indicates that the recipient address was rejected, not the sender address and I've always used inoc to contact them about my transit circuits.