Error Code Portal
MicrosoftWindows WinHTTPError code

12166

ERROR_WINHTTP_BAD_AUTO_PROXY_SCRIPT

Alternative forms: 0x00002F86 · 0x2F86 · ERROR_WINHTTP_BAD_AUTO_PROXY_SCRIPT

What does this code mean?

Code 12166 · An issue reported by Windows WinHTTP.

Official explanation · Original text

An error occurred executing the script code in the Proxy Auto-Configuration (PAC) file.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

Error Messages (Winhttp.h) ↗

Creator: Microsoft and MicrosoftDocs contributors
License: Creative Commons Attribution 4.0 International
Checked on: 2026-11-12

Modifications: Extracted numeric codes, symbolic names and English message text; converted Markdown/HTML to plain text and normalized whitespace; added Korean product context, namespace labels, status classification and separately labeled official links. No machine translation of message text.

Source details · Original licenses and notices