Hello @Soumyadip Chatterjee ,
How did you login to the Azure Container Registry ?
Are you using Admin Creds or your own AD identity ?
Can you login by using and perform : az acr login --name my-container-registry
Some times there might be a bearer token authentication challenge issues
Other ways to login is:- You can enable admin account on ACR and try logging into using admin username and password and try out
https://learn.microsoft.com/en-gb/azure/container-registry/container-registry-authentication?tabs=azure-cli#admin-account
If you are not able to login successfully , this document should help you out: https://learn.microsoft.com/en-us/azure/container-registry/container-registry-troubleshoot-login