Stuck on loading after install


I installed Webiny and opened it on localhost:3001. It asked me for user info and password, and then it gets stuck in a loop. It shows “Loading locales…” and then “Checking apps…”, then nothing, just the orange loading icon.

If it helps, in the dev console, I have the error : Uncaught (in promise) Error: GraphQL error: secretOrPrivateKey must have a value.

Any help would be very much appreciated… :-S
Thank you !