I’m posting this here in case other players experience this issue. Today I got this error code for the first time ever while attempting to start Valhalla, Odyssey, and Origins. I didn’t try other AC titles at the time. My Internet connection is strong and I didn’t have trouble playing other games and apps that required an Internet connection.
The problem seems to have gone away after restarting my XBox Series X. Not sure why, but if anyone else experiences this issue, try restarting your system.