@Eli.Harris 

First start with the physical.  This would start at the cables.  You want to make sure the Ethernet cable going from the ISP modem to the router is working.  Take the Ethernet cable and connect it to the Router's WAN (blue port) and LAN (one of the yellow ports).  Now look at the front of the router and check to see if the LAN and WAN lights are lit.  These lights look like Saturn and a computer monitor.  If they are lit this means the router's ports and the cable are working.  Next take the Ethernet cable from the Router's WAN to the modem.  If the light for WAN does not go on this would indicate a bad port on the modem.  And that would be the cause of your concern.

If the light does light up but it Amber then you likely are dealing with MAC Binding (especially if your ISP is cable)  If that is the case try this.  If you do not have Cable but the light is amber then contact your ISP and see if the WAN needs a specific setup.  Fiber and DSL porvides often do have a special setup.  

If this does not help please provide more details and pictures of your setup so we can try to help further.