# X_CLIENT_ERROR

## Means

a browser reported an uncaught failure

## Typical cause

an app/ page threw in the browser: a window error, an unhandled rejection or an island whose mount() rejected — the report's cause is the browser's own message, capped, and meta.clientBuild is the build the tab was rendered by

## Fix

`x shot <route> --json`

[Core and runtime](/error-codes#core-and-runtime)