Update: We've temporarily fixed the issue with the Strava connection dropping by disabling the Strava search feature through the Zwift Companion app. Once we find the root cause of the bug, we'll enable the search feature again.
There's currently an issue where your Strava partner connection with Zwift can become disconnected. This will prevent your Zwift rides from auto-uploading to Strava, so if you complete a ride and don't see it upload, you may want to double-check your Zwift dashboard connections. We'll continue investigating this together with Strava and provide more information as it's available.
While your rides won't automatically upload, you can still manually upload them as described here. See the sections on "Downloading your .fit File from your Dashboard" and "Finding your Local .fit File" for instructions on how to find your activity.
You can then upload the file following the instructions on Strava's support site.
We've also temporarily disabled the ability to disconnect your Zwift and Strava accounts in the hopes that this will prevent the connections from automatically disconnecting.