do you mean when you go to the Main Menu and then click on the Quests icon there? I checked and it looks to be working on my end, but can you post a screenshot?
I've been trying to find a way to replicate the error but I can't seem to, so just checking again - are you using the browser version or one of the downloads? And if you're using the browser game, what browser are you using?
There's a chance that your browser might not be accepting cookies so some parts might not be showing up - have they been enabled already on your browser settings?
ahhhh, there are some reports from users that after the latest android update a lot of the RPGM games don't work because it tries to run configuration errors more than once and screws up the game. I downloaded joiplay myself and tried to play my game there as well, and it runs up that same error with the quests, so I think the joiplay app itself might be the problem