Assigne user assigned managed identity to Container Instance

Hi Team,

I am trying to access azure keyvault inside my container instance app. However, I am not getting the proper response.

1. Creates Web APi with DefaultAzureCredential
2. 
3. Able to retrive the data using aboe code.
4. Built image and pushed into Azure container registry
5. Created user defined managed identity
   1. az identity create --resource-group "POCRG" --name "AcIdSample20240530101995"
6. Provide keyvault secret user role to above identity
7. Created a container and assigned above identity
   1. az container create --resource-group "POCRG" --name "democmdapi-userassigned" --image "sample20055.azurecr.io/net5:latest-windows-cosmos-v2" --assign-identity "/subscriptions/f9356ed2-112486e/resourcegroups/POCRG/providers/Microsoft.ManagedIdentity/userAssignedIdentities/AcIdSample20240530101995" --os-type "Windows" --registry-username "Sample02055" --registry-password "2ITH1E7gn0oujgaZ+ACRA+SoJX" --dns-name-label "api-dem-az2-user-assigned" --ip-address "Public"
8. When I try to access the application, it is giving an error

9.    ManagedIdentityCredential authentication failed: DefaultIdentityNotDefined \r\nStatus: 404 (Not Found)\r\nErrorCode