Hi NewJob101,
It's great to hear you're familiar with MYOB already. If the In Tray is greyed out even though it says you're online, it usually means your user access doesn't have permission to use the In Tray.
I'd suggest checking with whoever manages your MYOB setup to confirm your access. Here's a link that can assist with managing roles and permissions: Manage users.
If you're still having trouble, reach out to our live chat support through our virtual assistant MOCA or submit a case via MyAccount and they'll help you get it sorted.
Regards,
Sai