Email domain @protonmail.com is not supported

I’m failing to understand why ProtonMail email addresses are not supported for user account sign-up. Why is this this way? What’s your business justification? And do you support other secure email providers such as Hushmail or Tutanota?

hi there, we’re happy to speak to this. Unfortunately, we had to restrict access to our service for protonmail (and a few other email providers) some time ago (more than two years - it is not a recent change)

We found that, when we allow protonmail email addresses on our system, we experience an extreme uptick in accounts with spam, fraudulent activity, phishing, illegal (by US law) pornography, dmca violations, and things of that nature. The extent was so severe that our paying customers, search engine results, and legitimate business side of things were being negatively impacted. We understand that blocking an entire email provider is quite drastic, but it was the only way to mitigate the impact on our service.

I don’t have information on hand at this second as to which email providers are on our list of frequently abused services, so you might find that one of those providers you listed does work, but unfortunately protonmail does not and likely will not be unbanned as the security risk is simply too great.

I wish I had better news for you! If you have follow up q’s, I’d be happy to try and answer them.

The SSO issue still boils down to: “Email domain @protonmail.com is not supported”.

We use an email address as a primary identifier for a user. When you use SSO for sign-on this still connects to a specific user and that user is still identified by an email address.

For Git host SSO (Bitbucket, GitLab, GitHub), if the email address which is primary at the Git hosting provider used is a ProtonMail email address, then you run into the same issue.

The solution for this is to use an email address which isn’t hosted there. If you make ProtonMail email address secondary at GitHub and make some other email address primary, the error above will not occur.