Hey there 
Do you see any errors in the dev tools console (F12) when loading in?
I did see a recent report from another user who mentioned that they were having the same issue until they downgraded the dnd5e system from the latest version. If you recently upgraded your dnd5e version, it’s possible that there’s a conflict of some kind.
On the grey screen issue (there’s an article delving into that a bit here, which you may have already seen The Gray Screen), if you’ve already checked without modules enabled (safe config), checked your world size, and ensured your hardware acceleration is enabled but still can’t get in, please make a ticket in the #ticket-support channel of our Discord server and post an invite to your game there with a link back to this post, and I can hop in with you to try to troubleshoot it from the inside 