What are two possible reasons why a scheduled nightly backup of ISE to a FTP repository would fail? (Choose two.)

What are two possible reasons why a scheduled nightly backup of ISE to a FTP repository would fail? (Choose two.)
A . ISE attempted to write the backup to an invalid path on the FTP server.
B . The ISE and FTP server clocks are out of sync.
C . The username and password for the FTP server are invalid.
D . The server key is invalid or misconfigured.
E . TCP port 69 is disabled on the FTP server.

Answer: A,C