> but they simply don’t allow signing up with my custom email domain. Tried 4 different domains. 3 of email services of various kind. 4th one my private domain

> but they simply don’t allow signing up with my custom email domain. Tried 4 different domains. 3 of email services of various kind. 4th one my private domain which has absolutely no email reputation because I use it only for internal emails and sending is not even possible. In the end I dug out some old gmail address and tried to use that. The error was always the same, there had been suspicious activity from that domain. So the message is definitely incorrect. Well, there could have been suspicious activity from some gmail address, but if they don't allow gmail I guess they don't want many customers. Yeah, did not cover my tracks. The could easily notice that I was the same one trying to sign up repeatedly with different emails.