Migration Manager Dropbox

Question

Migration Manager Dropbox: authentication fails immediately after the OAuth popup opens, before I can click Allow. I removed the Dropbox enterprise application from Microsoft Entra ID. The error message is 'Authentication cancelled'.

Answer 1

The “Authentication cancelled” message indicates the Dropbox OAuth flow is being aborted on the Dropbox side as soon as the consent window opens, so the focus needs to be on the Dropbox app and OAuth configuration rather than on the removed Entra enterprise app.

Use the following checks and fixes:

1. Validate Dropbox OAuth 2.0 configuration
   • In the Dropbox App Console, open the app used for Migration Manager/Dropbox connection.
   • On the OAuth 2.0 (or equivalent) settings tab, verify:
     • App key and app secret are valid and not regenerated without updating them in Microsoft 365.
     • Redirect/redirect URI and other OAuth parameters match what is required by the Microsoft 365 Dropbox integration.
   • Misconfigured OAuth 2.0 settings can cause Dropbox to immediately terminate the flow and return an “Authentication cancelled” style error.
2. Ensure all required permission scopes are granted
   • In the Dropbox App Console, confirm that the following scopes are selected:
     • Individual scopes: files.metadata.read, files.content.read, sharing.read, file_requests.read
     • Team scopes: team_info.read, team_data.member, team_data.governance.write, team_data.governance.read, team_data.content.read, files.team_metadata.read, members.read, groups.read, events.read
   • If any required scope is missing, Dropbox may not present a valid consent screen and can cancel the authorization.
3. Confirm the Dropbox admin account used in the popup
   • When the OAuth popup appears, ensure the account that would be used:
     • Belongs to the correct Dropbox Business/Enterprise tenant.
     • Has an active team admin role.
   • If the account isn’t a team admin or is inactive, the team access token authorization can fail immediately.
4. Refresh credentials and reconfigure the connection
   • In the Dropbox App Console, copy the current app key and app secret.
   • In the Microsoft 365 side (Migration Manager/Dropbox connection configuration), remove any existing Dropbox connection and recreate it using the latest app key and secret.
   • Start the OAuth sign-in again and watch whether the popup now stays open and shows the consent page.
5. Test the Dropbox app’s OAuth flow independently
   • If the popup still closes instantly with “Authentication cancelled,” test the same Dropbox app’s OAuth 2.0 flow outside of Microsoft 365 (for example, using a simple OAuth test harness or Dropbox’s own tools).
   • If the flow fails there as well, the problem is entirely with the Dropbox app configuration (OAuth settings, scopes, or credentials) and must be corrected in Dropbox before Microsoft 365 can connect.

After OAuth succeeds and the Dropbox connection is established, continue with Migration Manager’s Dropbox steps (scan and assess, then migrate). Use the scan reports only for content-level issues; they won’t fix the OAuth problem, which must be resolved in Dropbox as above.

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References:

• Troubleshoot issues with the Dropbox Microsoft 365 Copilot connector
• Step 2: Scan and assess Dropbox folders
• Unsupported files in Migration Manager