@Bahram Thanks for the update and glad to know the issue got resolved!
The problem was a wrong value coming from the AppSettings which was not obvious in the code. it should be https://accountname.blob.core.windows.net but instead, it was https://accountname.blob.core.windows.net/ContainerName.
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Posting the answer behalf the @Bahram ! Please do Accept the answer and upvote your answer this can be beneficial to other community members.