IoT operations_Blob_Authentication_Access key not working

I am trying to use Authentication Access key for Azure Blob storage source, but when entering access key of storage account and saving the pipeline it gives error "Data pipeline httptoblob has been saved, but a problem occurred synchronizing your changes.

Message: {"code":"HandlerSchemaValidationFailure","errors":["authentication: Must validate one and only one schema (oneOf)","authentication.accessKey: Does not match pattern '^[a-zA-Z][a-zA-Z0-9-]$'"],"message":"Stage "output" failed schema validation: authentication: Must validate one and only one schema (oneOf), authentication.accessKey: Does not match pattern '^[a-zA-Z][a-zA-Z0-9-]$'.","target":"output"}

Code: HandlerSchemaValidationFailure".