Working on demo of calling AD secured function app from another function app. All testing went fine on my local machine however below error was thrown while testing after publishing it to portal. Error 2020-01-08T09:52:07.451 [Error] Executed 'CallerFunctionHttpTrigger' (Failed, Id=e8d196b0-b077-447d-a8d8-07458c4873cb) 'authority' Uri should have at least one segment in the path (i.e. https://<host>/<path>/...) Parameter name: authority Why it happened In my code am referring to TenantID  to form the authority URi ,which is to be fetched from AppSettings at runtime. And below are the lines of code which is to get the access token from Azure AD and error was thrown against the first line (marked in yellow)  AuthenticationContext authenticationContext = new AuthenticationContext ("https://login.microsoftonline.com/"+ Environment.GetEnvironmentVariable("TenantID")); ClientCredential...