I installed two Cisco ISR4331routers in my SOHO model and they are both set up with a GLC-GE-100FX fiber interface add on module for gigabitEthernet port 0/0/2. One only has two ports being used right now, the GLC and a standard RJ-45 port and the fiber port is up, cable showing green triangle. The other router is using all three ports, the 2 RJ-45's and the fiber on GI 0/0/2. When I run do sh ip int br, the port shows as up but the fiber cable installed in the 0/0/2 port is down with the red triangle. Does anybody know why this may be? IP and subnet mask are good. IP 10.0.0.1 mask 255.0.0.0 on the down one and 10.0.0.2 255.0.0.0 on the other end of the cable showing green.
I will check to see if maybe I have the cable installed correctly on the router. I am using a PC not a Mac. Also using Win10 Pro. Thank you. I will post again once I have it figured out. Likely it's something simple.