We no longer support Persona for logging into MDN. Please link your GitHub account to your MDN profile now so you can continue to sign in to MDN.
Starting on November 1, 2016, we only support GitHub for logging into MDN. If you didn't add a GitHub login to your MDN account before we disabled Persona logins, please file an "Account Help" bug on Bugzilla.
We recognize that this is an inconvenience, and we do apologize for it. Unfortunately, this was out of our control. See Why was Persona removed? for details.
Mozilla has shut down the Persona project, and its servers will be turned off in November, 2016. You can learn more about Mozilla's decision to shut down Persona on the Mozilla wiki. We disabled Persona login support on November 1, 2016, leaving GitHub as the only authentication method for the time being.
We would very much like to do so, but have not yet identified another provider which meets our requirements; in addition, we don't currently have the developer resources to integrate another provider. For the time being, your only option to keep contributor access to MDN is to link your MDN profile to your GitHub account. If you are unable to do that, please file an "Account Help" bug on Bugzilla.
Keep in mind, of course, that you don't need to sign in to MDN in order to read our content. But if you wish to contribute to MDN, that does require an account with an associated GitHub login.