network issue invalid IP address

I have a lattitude 5491 this am I booted up and wireless connected to modem but with no internet access. tried resetting the modem, rebooting the computer no luck. ran troubleshooter and it said the IP address was invalid.

I then tried to tie on to my iphone and it attaches just fine and I have internet access.

tried again tonight to access internet through the network modem. same issue and still can tie on to my iphone.