The easiest way has three steps as follows:
Search: search your desired package in pypi.org
Download Package: after search and select desired package, from left icons, select "download files" and then choose your desired version witch is compatible with your operating system, and just download package with .whl format. for example for pytorch package, select and download "torch-2.5.0-cp312-cp312-win_amd64.whl" witch is compatible with pc operating system.
Install: put downloaded package into a folder named Repository on your Desktop and then run cmd in this folder and write below command:
pip install tensorflow-2.17.0-cp312-cp312-win_amd64.whl -f ./ --no-index --no-deps
Hint1: instead of "tensorflow-2.17.0-cp312-cp312-win_amd64.whl" part of command, put complete name of your downloaded package.
Hint2: to run cmd in your desired folder, just write cmd in address bar of that folder.
This Method Install your desired package and you will have no more ProxyError.
GoodBye.