Link launches in Safari instead of using existing app
When clicking a link in an email or in social media, the link will open in Safari (or sometimes the App Store) instead of in an app used every day. Two examples include New York Times and the My Doctor Online (from Kaiser).
What this almost always means is that I am forced to login to the respective website; and my credentials seem to be required every time, and don't seem to be saved in iCloud passwords (which I have enabled on all of my devices).
Note to Community Support bots: please do not politely include a generic link as your answer, such as "App Stops Responding", or suggest restarting or reinstalling the app (which I have done). Please answer the question directly, or let other knowledgeable members respond instead.