I think the reason why some players of AC Valhalla are getting the error code 0x00000004 when attempting to access online content or Ubisoft connect is because they are playing on the Xbox X. I am currently playing on the latest system and the Xbox One S and have no issue connecting when playing on the last gen console. If I then continue on the Xbox X I get the error ever time. I think quick start is the possible cause so Ubisoft need to look at that as part of the root cause. If you happen to have both systems then play the game on the older console of you want challenges etc to update. Otherwise it looks like you will have to wait for the developers to fix the issue before the Xbox X will have its connection problem resolved. Pretty poor if you only have the new console as you may lose out on the timed challenges and their unlockables. Whether Ubisoft take that into account and extend the time frame so no one misses out is another matter.