@MisbahHasan-4008 Apologies for the delay in response.
The VM's in the host pool must be Standard domain-joined or Hybrid AD-joined. Virtual machines can't be Azure AD-joined (in the future, AAD joined will be supported). You will need to either deploy or use an existing Domain Controller, or leverage the Azure Active Directory Domain Services (AADDS, not to be confused with AAD) in order to do a Standard domain-join.
Please review the requirements for WVD here.
To learn more about the different identity solutions used with WVD you can find more information here.
Similar issue has been reported here and has troubleshooting steps for the issue reported as well. One more article referring to similar issue is here.
Please let me know if above helped or not.
Please 'Accept as answer' if it helped, so that it can help others in the community looking for help on similar topics.