When you have cloud sync enabled, Marvin communicates with the sync server to sync your tasks and other data. This communication is "authenticated" so that only you can access your data. Marvin has two ways to authenticate, and when both fail, your sync will not work! You'll see errors in the console like error: _reader access is required for this request. This guide will help you understand this error and what you can do to get sync working.

What this error means is that Marvin is trying to sync your tasks, but without being able to prove to the server that you are who you say you are.

With "basic authentication", Marvin sends your sync credentials directly to the server using the "Authorization" HTTP header. For those who use Marvin at work, this sometimes fails since work firewalls sometimes block this header in the name of security. You can check if basic auth is being removed by your firewall using the sync health check:

If you see "Request integrity: No", then make sure 3rd party cookies are enabled! See below.

Marvin can also authenticate by sending a session cookie to the sync server. Since this server isn't at amazingmarvin.com, a "3rd party cookie" is used. Some browsers, like Brave, block 3rd party cookies by default, and most browsers have the option to block 3rd party cookies for the sake of privacy. We recommend that you allow Marvin to use 3rd party cookies so that Marvin can create session cookies for the sync server, especially if your firewall is blocking basic authentication (as described above).

Please contact support if you need help enabling 3rd party cookies for Marvin.