Have you ever had berries from it? Were there any signs of flowers earlier in the year? Just wondering if you have a male tree - if that is the case, then no berries ever. If unsure, try planting a female tree near at hand (if you have room for another), something like Golden King ( which, in spite of it's name, is a female), or any other female tree that takes your fancy.
We have several holly trees at the bottom of our garden, including Golden Queen, which is a male - just to confuse the issue!! You do need both with in a fairly small area to flower and berry well - we have quite a good crop of berries this year, which rather surprises me considering the dreadfully cold spring we had when the pollinators shoud have been about. If your tree is female and a neighbour has a male then you should get berries - even the so called self fertile ones do better with a male for pollination.