Hast du PBSZSize auf 0 gesetzt und PbszAsync ausgeführt sowie ProtLevel auf P gesetzt und ProtAsync ausgeführt?
Siehe Kommentar im Quelltext:
Zitat:
How to use FTPS (TLS/SSL/Implicit SSL) ? - V2.106
First you need to have ICS-SSL and recompile the component and your project
having symbol USE_SSL defined. Then specify the SSLType, either use
explicit command AUTH after Open command to request TLS/SSL protection of
the control channel on standard port from server, or you may use one of
the high level commands which will automatically invoke Auth TLS/SSl once
connected to the server. Implicit SSL is another method that establishes
always a secure control channel (no AUTH command is required). To protect
the data channel as well issue "PBSZ 0" and "PROT P" once the control
channel is protected, or "PROT C" to clear the data channel.
Currently there's only one spec available specifying explizit SSL (AUTH TLS)
it's RFC4217.