Which platform did you purchase the DLC on and which platform are you trying to access that content on? DLC licenses are bound to the platform where they are purchased; Cross Save cannot transfer these licenses to other platforms, so you must buy them on each platform you want to access that content on. As for Season Passes, they are tied to the characters that log in first after the purchase and can move between platforms with Cross Save because they're in-game purchases (like other items you can buy with Silver). But because of this, it's highly recommended to set up Cross Save before buying any Season Passes as it's possible to bind them to the account you don't plan on using in Cross Save.