Gears 5 entered Early Access Thursday, but many players are no-doubt frustrated by server issues both on the studio's end and with Xbox Live, the latter of which extended late through Friday night. At least on the developer's end, The Coalition Studio released an update Friday morning that server stability had "dramatically" improved, noting that they would be monitoring the situation and issuing new updates as needed. Xbox Live says they're aware of the situation and are working toward a solution.
Our teams are aware & currently investigating errors when attempting to sign in. We'll update here & on our status page: https://t.co/PzAdjUFMJj when we have more info to share.September 7, 2019
Those affected can keep an eye on the Xbox Live servers via the Xbox Live Status page, which currently shows a Limited status for both Xbox Live Core Services and Purchase and Content Usage. "Our engineers and developers are actively continuing to work to resolve the issue causing some members to have problems signing in to Xbox Live. Stay tuned, and thanks for your patience," reads the latest status update.
To make matters worse, even solo players are experiencing issues in offline mode, where the Error Code 0x80004001 is asking players to search for "ESTANA" on Gears 5's support site. At the time of this writing (8:30pm PT), the search term doesn't provide any results.
If you do manage to slip through the filter and gain access to Gears 5's online multiplayer, you might notice some of the content you've unlocked not appearing. In that case, Coalition recommends a hard reset and logging in again. If all else fails, try submitting a support ticket.
Wait as patiently as you can for Xbox Live while catching up on everything we know about Gears 5's gameplay, story, and everything else.