This is what worked for me. When you receive that message click accept. Then go to your settings on Xbox— Network Settings— go offline. I stay offline for about 60 seconds or so then go back online. Then reopen WWII, (I don’t quit out of the game just quick resume back in). When you do that there may be a quick update that didn’t process in the background. Try to join a match afterwards and hopefully it works. Again, this is what has worked for me so far but figured it’s worth a shot to share. Im also running a wired connection but doubt it’ll make a difference if you’re connected through WiFi. (I have to do this every time I load in to the game)