Hi @Manoj Tamarana , sorry for the delay in response.
Deleted applications sometimes take a while to fully purge from the system. Check the Entra ID Recycle Bin to see if the deleted application is still there. If the application is still listed there, you can either wait for it to be fully purged (which might take some time) or try to restore it and then properly delete it again.
If the application is not in the Recycle Bin, there might be stale entries in the backend. Sometimes, running a PowerShell script to clear these entries can help.
Connect-MgGraph -Scopes 'Application.ReadWrite.All'
Get-MgServicePrincipal | Select-Object DisplayName, AppId
Remove-MgServicePrincipal -ObjectId <ObjectId>
Please let me know if you have any questions and I can help you further.
If this answer helps you please mark "Accept Answer" so other users can reference it.
Thank you,
James