Hi @Richa Kumari,
Ensure user should have Virtual Machine User Login or Virtual Machine Administrator Login role
In Azure portal go to WVD VM > Select Access control (IAM) > Select Role Assignments > Confirm the User account has been granted Virtual Machine User Login or Virtual Machine Administrator Login.
Checked have the necessary licenses to allow multiple users to connect to the virtual machine.
Ensure RDP property targetisaadjoined:i:1 was added to the AVD host pool. So, add going through. Navigate to Azure portal > select host pool configured for Azure AD Joined > select RDP Properties blade > Select Advanced Tab > added- targetisaadjoined:i:1
May have "per user MFA" enabled - which does not work with AVD, disable it. as per: Log in to a Windows virtual machine in Azure by using Microsoft Entra ID - Microsoft Entra | Microsoft Learn
If you have any further queries, do let us know.