What is the total distance you are running?
What type of devices on each end?
What speed are the devices set to?
62.5 micron MM fiber is limited to a total distance of 2KM for most devices, but the devices must be rated to operate at that distance. Some devices are rated to shorter distances, so check the spec sheet.
Also, speed settings on the devices matter as well. As an example, if the devices are two switches and the interfaces are forced to 1 GIG, the path could be too long to support that speed. They could work without issue at 100Meg but not work at 1 GIG.
What type of fiber tester was used to test the fiber?
The fiber could have dirty connectors and still "pass" depending on what type of tester and what type of test you are using to determine if the fiber is good.
1st, I would get some lint free cloths and isopropyl alcohol and properly clean each connector & jumper.To properly clean the fiber connectors, you grip the ferrule nearest the the point where it enters the housing and wipe in a twisting motion while moving out to the ends.
If this does not work, replace the jumpers at the junction point.
