Now, /verify can return 401 or 403 depending on the user authentication.
Every public API endpoints and pages return 200 with error message in
JSON body or 401 if the user is not authorized.
This policy makes it complicated for an attacker to know what is the source of
the failure and hide server-side bugs (not returning 500), bugs being potential
threats.
Before this fix, the application was simply crashing during execution
when connection to redis was failing.
Now, it is correctly handled with failing promises and logs have been
enabled to clearly see the problem
