We had trouble with our patchbay and decided it was likely our cheap tt patch cables from Ebay. Some tt cables needed to be turned to the right position and some had to be pulled out slightly to work properly.
Then we got these - NO problems at all. Highly recommended. Read more
I was told by a patchbay manufacturer that the tolerances are important and some cheaper tt connectors will cause issues. Expensive, but worth it if you can't afford to have problems.