Cisco SFP GLC-LH-SM unknown in Cisco Catalyst 2960X-24TS-L

[bluephoenix71]

Hi all,

Client installed a single mode fibre run from Distribution Switch to Access switch. The distance is not even greater than 100 Metres but the client insisted since the fibre is free.

on the Cisco Catalyst 2960X-24TS-L (Access layer not stacked) the SFP is identified, but on the Cisco Catalyst 2960X-24TS-L (Distribution switch stacked) the SFP module is "unknown".

access_sw#
Gi1/0/49 access_sw po notconnect 1 auto auto 1000BaseLX SFP

dist_sw#
Gi1/0/49 dist_sw po notconnect 1 auto auto unknown

Distribution switch is running 150-2.EX4
Access switch is running 150-2.EX5

I have configured on both sides
speed nonegotiate, above output is showing that the 2 are not even talking to each other since their status is still auto auto...

Any ideas is gladly appreciated!