What is a timezone / IP mismatch?

A common, cheap check compares the IP's geolocation with the browser's reported timezone, language and locale. A real user in a place usually has all of them line up; a session routed through a proxy in another country often keeps its home timezone and language.

No single value is wrong, but the combination is implausible — the essence of coherence-based detection, and one of the easiest checks to fail when you add a proxy naively.

The fix is to move timezone, locale and Accept-Language to match the egress, ideally derived automatically from the proxy's geolocation. Clearcote sets these coherently. See fingerprint flags.