gethostbyname: unknown error

I am unable to login to WinScp. I have been using it for the past 2 months for my college class. It has always worked fine, but now all of a sudden I am getting this error when I try to login:

gethostbyname: unknown error

can you please help me so that I can fix this problem? I am falling really behind in my class.

thank you so much

Do you know IP address of the server? Can you try to use it instead of the domain name?