Be aware of the case sensitive "Redirect URL" in Azure Active Directory App settings
When you create a new App in Azure Active Directory App settings, and then setup the "Authentication"->"Add platform" such as ("Web") -> add a redirect URL. Now go back to your client side applications either Web or mobile app, and then add the call back URL to the configuration settings. If you add the URL is upper or lower case different from the one in App settings, then you will receive the error "Incorrect URL" from Azure, and so make sure enter the URL as same as the settings in Azure.