Quick answer: Assign a valid render camera to a Screen Space Camera canvas (or use Overlay), set sane near and far clip planes, and make sure no camera has a degenerate position or projection.
This error comes from a camera projection that is invalid, frequently a Canvas set to Screen Space Camera without a proper camera. Here is how to fix it.
How to fix it
1. Fix the canvas render camera
A Screen Space Camera canvas needs a valid Render Camera and a sensible plane distance. A missing or misconfigured camera triggers the frustum error. Assign one, or switch the canvas to Screen Space Overlay if it does not need a camera.
2. Set valid clip planes
A near plane of zero or a near greater than the far makes projection invalid. Set the camera's near and far clip planes to reasonable, positive values.
3. Check the camera transform
A camera at an extreme position or with a zero or NaN in its transform produces an invalid frustum. Confirm the camera's position and rotation are finite and reasonable.
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 Unity 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.
Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.