iOS 9.3.5 no internet access through my app after adding a url scheme

After making an update to an app that only added a url scheme, all 9.3.5 devices fail to connect. The app opens but no intent access. If they upgrade to iOS 10 then it works fine. However, that is not an option for my iPhone 4 customers. Is there something that needs to be done in addition to support this iOS version?

I Added URL Types with the scheme and identifier to my Plist.

Edit: The problem is there whether they open the app normally or through a link.

After finally getting my hands on an iPhone 4, The actual error was "the resource could not be loaded because the app transport security policy" iOS 9 was the version that added this. I assume since the last update of the app was prior to iOS 9 that new updates to that version from older versions weren't affected. I had to add a key to my Plist retrieved from this answer

    <key>NSAppTransportSecurity</key>
        <dict>
            <key>NSAllowsArbitraryLoads</key>
            <true/>
        </dict>