The second case would be with your Antivirus. There are proxy settings enabled under your settings of any security programs that you may be using. If you cannot find the procedure to stop it, you can ask our techs on chat support to guide you.
https://www.officelivesupport.com/error-0x80071a91/
[Fixed] Window Error Code 0x80071a91 Solutions
Error Code 0x80071a91 error code is common for all the Windows Operating systems when you try to install the updates. It usually appears when Windows 10 or Windows 7 update system is broken or there are network-related glitches.
Usual causes for this Error Code 0x80071a91are communication failure over the internet with Microsoft update servers.
Firstly, I will suggest you do Windows Troubleshoot for Error Code 0x80071a91.
