Problem with cisco 1720 an frame-relay

Hi to all, i'm paolo from italy
I have a problem with a cisco 1720 with frame-relay.
Sometimes it is impossible to navigate in internet, but the PVC between the router and Telecom is mark as active, and with the command debug frame-relay lmi it seems that all are ok.
the result of sh frame-relay pvc, sh frame-relay map and sh frame-relay lmi is ok, so the connection is up! but i can't surf the web! i can re-surf the web only if i reload the router.
Anyone can help me? :
:evil:

Can you surf with IP vs URL to validate DNS issues? Maybe paste a show run and show start before your re-load so we can stare and compare?

Can you surf with IP vs URL to validate DNS issues? Maybe paste a show run and show start before your re-load so we can stare and compare?

I can't surf with ip, too. The run and start config are the same.