I, for the life of me cannot get the White and Yellow hoses to connect on the FEL. The Blue and Red connect fine, oh yeah it's on a Bx 2670 with LA 243 loader.
Make sure pressure is released on both sides of couplers. The tractor side is easy just cycle the stick in all directions with motor off. Sometimes the way you parked the loader will make it have pressure on a coupler so grab a rag and a punch then depress the plunger inside the coupler to release the pressure. (Wrap the rag arround the punch you could possibly get a big spurt of fluid)
Yep, I'm going with given advice so far. One of two things here, you've uncoupled them with a load on them (pressure) or you uncoupled in cool weather and are now trying to recouple in hot weather (fluid expanded).