I have an app that works fine on Android, and works fine on iOS for non-Outlook clients. In fact, it even works for some Outlook clients. It only fails when the Microsoft Advanced Threat Protection (ATP) is enabled on the recipient's server. This pads my URL within a https://xxxxx.safelinks.protection.outlook.com/?url=my_url&data=to_email_address_and_data
I have noticed that if I click on the Apple Store link that we send in an email that gets ATP applied, it opens Safari, Safari prompts
Open in "App Store"?
then the App Store opens.
What do I need on my website to make this happen?
I don't believe that this is a duplicate of Android Deep Linking with emails as I don't have an issue with Android.