MapVS records offline first and syncs when connected. If a recording is stuck local, something in that pipe is broken.
Check 1: are you signed in?
Open the app. If you're on the sign-in screen (not the map list), the sync target is gone. Sign in - your local recordings will queue for upload.
Check 2: is the phone online?
Cellular data or wifi must be reachable. Airplane mode or a captive-portal wifi will silently block sync.
Check 3: force a sync
On the iPhone app, pull down on the Recordings tab to trigger a manual sync. Any queued recordings will upload with a progress indicator.
Check 4: inspect the queue
Settings > Sync Queue shows every recording waiting to upload with its last error (if any). If you see "Auth failed", sign out and back in. If you see "HTTP 500", contact support.