The Team Files app needs access to an external URL to work correctly. This is essential to enable the Microsoft 365 Web apps, allowing you to preview and edit documents in Confluence Server/DataCenter with the Team Files app. If your server is configured to have limited access to external URLs, you’ll need to add the Team Files URL to the whitelistallowlist.
Add to your firewall’s
...
allowlist
To add the Team Files URL to the whitelistallowlist:
Open your server’s or network’s management setup;
Go to the firewall configuration;
Add
https://confluence.teamfiles.app
to the whitelistallowlist.