There are a lot of companies out there that force their clients to go through a proxy in order for them to reach the Internet.
This proxy is usually set in Internet Explorer, and can sometimes cause a slightly annoying pop-up asking for credentials every time you visit a web site.
Here is a short guide for how you can enable automatic login for all Internet sites using a GPO.
How to automatically log in with current user name and password
Note: These security settings are often controlled by a GPO, so it might not be possible to do this setting in your environment.
1. Go to Internet Options in Internet Explorer
2. Go to the Security tab -> Select the Internet zone -> Select Custom Level
3. Select what kind of User Authentication you want. If you never want to be prompted for credentials, select “Automatic logon with current user name and password.”