Netgear CM700 Cable Modem Issue

> I'm getting connection via wifi but when I try to connect my laptop
> directly to the modem I get no connection. [...]

   A CM700 is a cable-TV modem, not a router, and not a wireless router.
If you're "getting connection via wifi", then I'd guess that you have a
wireless router somewhere.

   Cable-TV ISPs can be fussy about the equipment which you connect to
their systems.  If you replace some (unspecified) router with a your
(unspecified) "my laptop", then the ISP may see a different MAC address,
and that may cause a connection problem.  You might want to contact your
ISP about this problem.