How to Remove Remembered User Credential

We have a laptop (Lenovo Thinkpad x131e) with Windows 7 Home Premium 64 bit.  Several people use it for VPN connection to work. Since users have different permissions on the work network, they can access certain network folders based on permission. Starting recently, all users can access all folders regardless of their permissions.

We use two vpn methods: one is Microsoft remote access, another is Palo Alto Global Protect. The problem happens with both vpn methods. It seems like the laptop remembers some user's network credential somewhere.

How should I should the issue?