Quick answer: Request pointer lock from a click handler, listen for lock change and error events to track state, and re-request on the next gesture after the browser exits it.
Pointer lock that does not work is usually requested without a gesture or not re-acquired after exit. Here is how to fix it.
How to fix it
1. Request from a user gesture
Browsers only grant pointer lock from a user-initiated event like a click. Requesting it on load or without a gesture is rejected. Tie the request to a click on the canvas.
2. Track lock state
Listen for pointerlockchange and pointerlockerror so you know when the lock is gained or lost. The browser can exit it (Escape, focus loss) silently; tracking state lets the game respond.
3. Re-request after exit
When the browser exits pointer lock, the mouse is free again. Re-request it on the next user gesture (a click to resume), rather than assuming the lock persists.
Catching the ones you can't reproduce
The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.
Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.
This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.
Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.