That is exactly what happened with mine. I checked it at the purchase inspection but never used it again till months later, when I couldn't get the fitting engaged. I happened to be at the factory for a tour and they agreed to look at this and the poor radio reception. The tech there couldn't get the fitting in either and said just have your dealer put a new one in. The also installed a new antenna, which made little difference in reception. At the dealer the tech took a screwdriver and a hammer, whacked it once and voila, engagement! There is a little ball that seems to get corroded in place. You do need to drain this or you'll crack the pex or the fitting in winter. Then you'll get to replace the fitting.
Ottawa Ontario Canada
2015 Solera 24R