Facebook SDK: app not registered as a URL Scheme

Follow these three steps:

1. Create a key called FacebookAppID with a string value, and add the app ID there.
2. Create a key called FacebookDisplayName with a string value, and add the Display Name you configured in the App Dashboard.
3. Create an array key called URL types with a single array sub-item called URL Schemes. Give this a single item with your app ID prefixed with fb. This is used to ensure the application will receive the callback URL of the web-based OAuth flow.

The finished .plist should look something like this:

Source Link:

In terms of raw keys and values you should have CFBundleURLTypes and CFBundleURLSchemes. Hope that helps!

there is another section below the info - URL Types

check that the values there, under the URL Schemes field match the value in the URL types -> URL Schemes in the property list above. (and also match the FacebookAppID)

For iOS 9

If you have an error: 'LSApplicationQueriesSchemes'

Based on Bear with me answer, you will also have to add those lines:

<key>LSApplicationQueriesSchemes</key>
<array>
   <string>fbauth2</string>
</array>

See this.

You should end up with those lines at the end of your .plist files:

<key>CFBundleURLTypes</key>
    <array>
        <dict>
            <key>CFBundleURLSchemes</key>
            <array>
                <string>fb2R3234544534554</string>
            </array>
        </dict>
    </array>
    <key>FacebookAppID</key>
    <string>2R3234544534554</string>
    <key>FacebookDisplayName</key>
    <string>stevejeff</string>
    <key>NSAppTransportSecurity</key>
    <dict>
        <key>NSExceptionDomains</key>
        <dict>
            <key>facebook.com</key>
            <dict>
                <key>NSIncludesSubdomains</key>
                <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
                <false/>
            </dict>
            <key>fbcdn.net</key>
            <dict>
                <key>NSIncludesSubdomains</key>
                <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
                <false/>
            </dict>
            <key>akamaihd.net</key>
            <dict>
                <key>NSIncludesSubdomains</key>
                <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
                <false/>
            </dict>
        </dict>
    </dict>
    <key>LSApplicationQueriesSchemes</key>
    <array>
        <string>fbauth2</string>
    </array>
    </dict>
    </plist>

* If you're using v4.6.0 or higher of the SDK, you only need to add:* (Thanks mohsinj)

   <key>LSApplicationQueriesSchemes</key>
      <array>
        <string>fbapi</string>
        <string>fb-messenger-api</string>
        <string>fbauth2</string>
        <string>fbshareextension</string>
   </array>