> "…but they don't accept Gmail addresses." "Registration with @gmail.com addresses is blocked due to abuse, please register with another address. You can chan

> "…but they don't accept Gmail addresses." "Registration with @gmail.com addresses is blocked due to abuse, please register with another address. You can change it later, once signed up and verified." However, apparently, you can register using a Google, Bitbucket or GitLab.com sign-in.