Unhandled error messages from `convert_to_der_and_cache` method when invoked

[Shivraj0]

Error messages handled and returned from method convert_to_der_and_cache is not consumed properly when method is actually getting called. Need to have error messages updated when calling convert_to_der_and_cache

[Shivraj0]

PR

[Shivraj0]

Hey @GUI , Can you kindly check this issue and review attached PR for the same ?