Entering credentials when accessing a network drive?

Question

Active Directory

There are domain PCs (laptops) win 10, network drive win srv 2016.
All in one domain, authenticated by domain accounts.
Users mounted a network drive (via GPO), when physically in the office when opening a network drive - get access (without entering a password).
When connecting via VPN, outside the office, when accessing a network drive, the "Enter Credentials" window opens, and the login of the user from the VPN connection is substituted in the login field. If you enter the correct domain login, password manually, then after restarting the PC, it will require you to enter it again. (the point to keep the data is marked)
Why so? how to fix?