Hi,
Welcome to Q&A platform.
Before we go further, may I know if the issue also occurred when configuring PAC file in IE or Edge? Or it only occurred when using some third-party browsers?
If the issue also occurred when using IE or Edge, I would suggest you could perform a clean boot on the problematic device which can help to narrow down if the issue were related to some third-party software.
For how to perform a clean boot in Windows, please kindly refer to the detailed in the following article:
How to perform a clean boot in Windows
Best Regards,
Sunny
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