Updated. I checked all my setting in MSFS2020 and found that the Data setting was set to OFF. So, I enabled Data to ON and some kind of out of date message and forced to log me out from Xbox. After I logged back my account and it detected an update for about not more than 200MB.
After the update, I tried to switch to VR mode when flying, WMR autostarted and now WMR windows without flashing screen and glowing sound…however, MSFS2020 turned to black screen. If I close WMR, MSFS2020 screen returns to normal. I think something wrong two days ago.
Tony