What are the EXACT error messages? What EXACTLY did you try? What are your EXACT property settings?
Umm, you are comparing a higher-level APPLICATION to a lower-level LIBRARY. Of course, a LIBRARY is going to be more flexible and thus require more configuration for meet your particular situation.
Seems simple enough. Please show the EXACT code you are trying to use to accomplish that.
Then you don't have TIdFTP setup correctly to match your server's requirements.
Those are not the only settings involved. What ELSE do you have configured EXACTLY?
Well, then you should have no trouble grabbing logs from CoreFTP and TIdFTP and compare them for differences. At what stage EXACTLY in the communication is the failure actually occurring? There are several different possibilities, which is why more DETAIL is needed.
Probably, but without any DETAIL about your setup or your server's requirements, there is simply no way for anyone here to know for sure what is actually wrong/missing.
Provided the server is actually reachable and responsive, most often a timeout error on a connect is due to a mismatch between the Port and UseTLS properties, causing Indy to wait for a server greeting that is never sent because the server is waiting for a TLS handshake from the client first.
Again, what is the EXACT error message? Is it an FTP-level error or a TLS-level error?
You can't set the UseTLS property to Explicit (or Implicit) without having an SSLIOHandler assigned first.