Router: TP-Link Archer C7 AC1750 v.5
ISP: RDS-RCS/DIGI (Romania), PPPoE.
When I plug the ISP ethernet cable into the WAN/Internet port, the router doesn't detect it, the WAN/Internet LED stays off, only the power and LAN1 are on. Also in the VLANS/Switch page the WAN shows "no link".
If I put another router in between, Archer router detects the cable from this router.
It's my first time using OpenWRT so I might be doing something wrong.