Proxy Password keeps changing automatically after I exit the settings screen

Dear community, I have a problem setting up a proxy and it's driving me crazy.

On my MacBook, I have set up everything according to the instructions my institution gave me - correct address, port etc.

The proxy requires a username (the email given to us by the institution) and a password. Once I enter everything correctly, click apply and re-open the settings window, my password is changed to a much longer one which I did not enter.

Here is the password length I entered:

This is the password length after I re-open the settings window:

The address, port, username is all the same - just a very different password. Therefore the proxy does not work/give me access to the specific websites I need the proxy for.

If I look into the Keychain Access program, the proxy has the correct address and the correct password I entered. Even if I open Chrome/Safari and I get the prompt to enter the proxy login details (and enter the correct login credentials), it still is the long/unknown password in the proxy settings.

I don't know what is going on here, or why the proxy does not work?

On my Windows PC I have set up the proxy the exact same way on the same WiFi network and over there it works as intended.

Could anybody help me out?

Thanks a lot!