Here are a few troubleshooting steps you can try:
1. Verify FTP server configuration: Double-check the FTP server settings on Cisco ISE. Ensure that the hostname or IP address, port number, username, password, and directory path are correctly configured. Pay attention to any typos or missing characters.
2. Check network connectivity: Ensure that there is network connectivity between your local system and Cisco ISE. Verify that you can ping the IP address or hostname of the Cisco ISE server from your local system. If there is a firewall in between, make sure that the necessary ports (typically port 21 for FTP) are open.
3. Verify FTP server accessibility: Test the FTP server accessibility from your local system using a dedicated FTP client like FileZilla or WinSCP. Attempt to connect to the Cisco ISE FTP server using the same FTP server settings configured in Cisco ISE. If the connection fails or you encounter similar errors, it indicates an issue with the FTP server configuration or network connectivity.
4. Check FTP server logs: Consult the logs of the FTP server (e.g., FileZilla or WinSCP server logs) for any error messages or indications of failed connections. These logs may provide further insight into the issue and help identify the root cause.
5. Validate directory permissions: Ensure that the configured directory path on the FTP server has the necessary read and write permissions for the FTP user. Incorrect permissions can result in errors when attempting to access or transfer files.
Please refer to the below link for troubleshooting the FTP Repository in ISE GUI
https://www.cisco.com/c/en/us/support/docs/security/identity-services-engine-software/215348-how-to-configure-repository-on-identity.pdf
