Some older analog sets care about polarity. SO first try switching tip and ring.
If that does not help, check the loop current through the set with the set off hook. If it is less than 23 milliamaps then that could be your problem. In that case you may need to use aa station card that supports long wire runs, or there may be a configuration options such as 24 verus 48 volts.
Let us know what you find.
Good luck