Could not retrieve directory listing. IP issue (Filter?)

Hello,
I have a weird problem.
When trying to connect to an FTP server of a client in Hungary, I get following error message:

Could not retrieve directory listing
I won't open a connection to 192.168.178.120 (only to XX.XXX.XX.XX)

The first IP is my internal IP of my PC in my network.
The second IP is my external IPv4-IP.

The protocol of the FTP server FTP & explicit FTPS over port 21.

Is there an IP or country filter at the FTP server or is it a setting on my site?
I tried it with FileZilla too, there I also can't connect, so it seems not to be a WinSCP-problem in general.

Thank you very much in advance,
Christian Hange

It looks like you are using the FTP active mode. Why? Did you try the default passive mode? In any case, post a session log file.

Thank you very much for your Answer.
I removed the tick in the checkbox at "Passive Mode" before, because i got other Errors with that:

Timeout detected. (data connection)
Could not retrieve directory listing
Error listing directory '/'.

Sorry, i forgot about that.
The attached log is on level 2 - Debug and in Passive mode.

No one an idea? :(

There's not much more I can suggest you that what they already suggested you at your duplicate post at FileZilla forum:
IP Block? Error: Failed to retrieve directory listing - FileZilla Forums