IPSec - Windows RADIUS - Administrator Alert - Error Code 5010

[costasga]

We are using pfSense in combination with Windows Server 2019 Radius for IPSec VPN. Users are authenticated properly and connections are established normally with mobile clients being given the IP defined in the Active Directory dial-in settings. However, in several cases the following error is encountered:

1. The user gets an error Subj: ** ADMINISTRATOR ALERT ** in the VPN windows (Windows 10)
2. In pfsense the connection is established properly
3. The event viewer registers the following error: "CoId={93156CFF-629D-46EB-BFCA-5588F43E4159}: The user XXX dialed a connection named VPN (IKEv2) which has failed. The error code returned on failure is 5010".
   Changing the IP address assigned to the user resolves the problem, but often it reappears.
   Do you have any clues as to what could be causing this issue?