So I am trying to connect two buildings via single mode Fiber we just had installed. one MS120-8 to another MS120-8 If I have both MS120-8's in the main office connected via their Fiber SFP's (both recognized by the switches) and connected via an LC/LC SM DPX cable they connect just fine. I move one switch over to the new building, connect it to the fiber panel ports 1&2 and at the office I have the office switch connected to port 1&2 on the fiber panel, via the same LC/LC SM DPX cables and they don't connect. I am at my wits end. I have had the fiber installers back out to check the fiber and its fine, I double checked that my SFP's are working and compatible, and again in the office the connect just fine. Any suggestion on what else I might do to try and trouble shoot the situation?  I have verified the SFP's work. I have verified , LC/LC patch cable are good, and the fiber installers tested twice now and say everything looks good. The fiber run is about 304 meters.  ... View more