On Wednesday 24th March, we plan to perform some database maintenance work. This will begin at 10AM GMT and is expected to last no longer than 1 hour.
During this time, users won’t be able to start new sessions on web. It may also affect mobile users who do not have courses downloaded for offline use.
We’re sorry for any inconvenience this will cause. We’ll keep users in the loop should we run into any issues along the way 
Thanks for your understanding,
Memrise team