5690adc created the issue

Under Data Channel Security I have enabled both; Try to use TLS for data channel and Use unsecured data channel if not supported.

But when I try to download a file from a ftp I get the following;

RETR blag-vh-prod.00
150 Opening BINARY mode data connection for blag-vh-prod.00 (15000000 bytes) using SSL/TLS.
QUIT
435 Failed TLS negotiation on data channel (not allowed), disconnected: Success.

and then it fails and doesn't try to use unsecure data channel instead. All I get is an Failure dialog with the options to Cancel or Try Again.