Stacked Access Switch port not showing up

[Tabish Hussain]

I have 3 access switch C9200 POE stacked and connected to 2 core switch stacked. Access and core switch are connected via LC-LC single mode fibre. However ports on both core switch 1 connected to access switch is showing up and green but the port between core switch 2 to access switch is showing up and green on core switch 2 while on access switch is showing down. Also access SW port is not blocked by STP (rapid pvst is enable). Also I can reach to internet through LAN cables connecting to RJ 45 ports of all 3 access SW. Can someone look into it and help me on this ?

Abbreviation - port= SFP port

For more info please refer to diagram. 

Thanks!

 

 

[Tabish Hussain]

I tried that earlier but port doesn't come up.

[Reza Sharifi · Accepted solution]

I tried that earlier but port doesn't come up.

So, that is not an STP issue. Most likely a layer-1 (physical) issue.

HTH