Azure Multi-Factor Authentication - Mobile App Approve not working

Team, We have users connecting to office PC's via Remote Desktop Connection. RDP Connection allowed only Mobile App Approval and Phone Call. Users were comfortable in using Mobile App Approval. But today Mobile App Approval Stopped Working. We are using Azure NPS Extension on the Radius Server. Users connecting to VPN is connecting via ONE TIME PASSCODE appearing on the phone. But for Remote Desktop Connection, the screen is not prompting to enter the ONE TIME PASSCODE. Phone CALL Authentication alone working for Remote Desktop Connection via MFA. Anyone facing this issue? Please share some suggestions.