Introduction

This error usually appears when a Facebook SDK integration expects the app to declare the Facebook URL schemes it can query or open, but the required scheme entries are missing from Info.plist. On iOS 9 and later, these declarations matter because the app cannot freely probe URL schemes without declaring them.

Add the Required Query Scheme

A common fix is to add the Facebook-related scheme to LSApplicationQueriesSchemes.

1<key>LSApplicationQueriesSchemes</key>
2<array>
3    <string>fbauth2</string>
4</array>

Depending on the SDK flow, other Facebook schemes may also be required, but fbauth2 is the one named in this error.

Also Check the URL Scheme for Your App ID

Facebook login integrations often require your app-specific URL scheme as well.

1<key>CFBundleURLTypes</key>
2<array>
3    <dict>
4        <key>CFBundleURLSchemes</key>
5        <array>
6            <string>fbYOUR_APP_ID</string>
7        </array>
8    </dict>
9</array>

If this piece is wrong or missing, login callbacks can still fail even after fixing the query-scheme warning.

Treat SDK Setup as a Whole

When this error appears, do not only patch the single string and stop. Recheck the full Facebook SDK integration setup:

• Info.plist keys
• app ID values
• URL scheme entries
• installed SDK version and setup instructions

Login integrations tend to fail at the weakest configuration link.

Common Pitfalls

• Adding only some of the required Info.plist entries and assuming the integration is complete.
• Forgetting the fbYOUR_APP_ID URL scheme while focusing only on fbauth2.
• Copying old Facebook SDK setup snippets without checking whether the current integration expects additional keys.
• Treating the error as a runtime bug instead of as a configuration problem.
• Editing the plist incorrectly so the app still ships without the intended scheme declarations.

Summary

• The error means required Facebook URL scheme declarations are missing from Info.plist.
• Add fbauth2 under LSApplicationQueriesSchemes when needed.
• Also verify the Facebook app-ID URL scheme under CFBundleURLTypes.
• Recheck the whole SDK configuration, not just one missing key.
• This is usually an integration setup issue, not an iOS runtime defect.