libcurl erros

Out of nowhere our installation of cscart has started having problems resolving host names. I am seeing this error when cscart tries to contact ups online tools, Authorize, paypal, and the error is like so:

Response: HTTPS: libcurl error(6): Couldn’t resolve host ‘

I am assuming it’s actually a server problem, but my host says nothing is wrong. this installation of cscart has been working flawlessly for months now, but all of the sudden these problems arise. has anyone else seen these errors or have a clue where to look for problems? i’ve been digging through server logs for days now and i think my head is going to explode. Help anyone?

Yes, it's a server/hosting issue. Sounds like your “resolver” is not configured correctly or the network your server is on is flakey. Contact your host for resolution.