The ongoing saga of Civilization VI seeing online cross-play broken between updates continues, with it now once again back online as of the update today, September 10.
A repeating issue: the game updates like most recently with the August 2020 release, cross-play has issues and gets disabled, then eventually it's sorted again. Hopefully at some point they will find the real cause of the constant breakage and actually sort it. Firaxis Games, the original developer, sent word yesterday that Aspyr Media were on it and today it's back online.
If you missed it, here's the overview of the last big update:
Going by their timeline roadmap for continuing to update Civilization VI with the New Frontier Pass, we should be seeing a new DLC released later this month with 2 civilizations, 2 leaders, a new game mode and other new content to be announced. After that another free update will come following their DLC - Update - DLC pattern with the following DLC to arrive in November.