@Carl Firmware was confirmed to be current while experiencing the connectivity issues. That leaves the cause to be a bad WAN port. I can see that as a possibility but given the number of other posts...

I have an Archer A7 router connected to a Verizon FIOS internet service. The ethernet cable from the FIOS box is connected to the WAN port on the A7. On average every 2-3 days, I lose internet access...