DIAGNOSIS Yeah, they didn't make it easy. The oil filter is tucked up against the frame rail, and a standard socket or wrench won't fit. It's a common first-service headache for every owner.
FIX You need a specific tool: a cap-style oil filter wrench with a thin wall, usually 65-67mm (or 2.5-2.6 inches). The one that often works is a metal cup wrench you use with a 3/8" drive ratchet. You might also get it with a short, flexible rubber strap wrench, but the cup is more reliable. Loosen it a bit from below, then you can usually finish spinning it off by hand.
IF THAT DIDN'T WORK If it's truly stuck, you can carefully drive a long screwdriver through the side of the old filter to use as a lever. Be prepared for oil to gush out when you puncture it. This is a last-resort, messy method.
HEADS UP When installing the new filter, hand-tighten it only—about 3/4 of a turn after the gasket makes contact. Overtightening is the main reason it's impossible to get off next time. And put a rag below it, you will spill some oil on the frame.