Why are the RJ-45 indicator lights not working?
When testing RJ-45 or RJ-11 cables, do not test live circuits. This device is designed for testing cables
The MT-7625 is compatible with ST, SC, FC, and 2.5 mm universal fiber optic connectors.
It can also be used with an LC adapter (5MT-7601-LC).
First, make sure you are testing with the same cable. Then check whether the spring contacts inside the port are uneven, misaligned, or deformed.