FTP connection and Wifi network profile

Some FTP error messages:
"Server sent passive reply with unroutable address 999.888.777.666"
"421 Failed to create data connection socket."

Other symptoms: success ftp authentication but failed folder content downloading.

I spent hours solving the problem.

One possible solution on Windows 10:
Check your Wifi connection type! Public or private?
Open Windows 10 settings --> Network and Internet -> Wifi -> Click on active Wifi connection
If the wifi network profile is public check out the private.
AND DONE!!!

I hope I save a few hours for someone else.