Android and FTP File transfer

Since I have a problem transfering files via USB, I tried the FTP Server on the Android device.
I tried several FTP Servers, I can connect, but not to the SD card.
Any hints?
FTP Servers currently installed:
Wifi FTP
and
FTP Server the olive tree
Best regards,

Stephan

FTP Server by The Olive Tree works and can connect to SD card (if you choose proper directory in configuration).
I tested some FTP servers and this is the only one that work with SD card I've found.

But after some time I installed Solid Explorer on my phone and now I prefer to connect Windows shared folders from android.

peterb,
thank you very much.
I found the problem, after you change settings with FTP Server by the Olive Tree,
you have to manually stop the connection (on the FTP Server) first and restart it.
Otherwise there is no effect.
I have access to the SD Card now!
Solid Explorer i googled and it sounds excellent, will try later.
Stephan

Using ES Explorer on Android side with Windows and NAS shares... works also good.