I’ve circled the ceiling mount holes in blue and the fan mount holes in yellow. As you can see, the fan mount holes are wider apart than the ceiling’s holes.
Also I’ve tried drilling into the ceiling. Drilling into the ceiling just leaves a hole and the screws fall right out.
The fan is a “fanimation” fan. My house was built in the 80s
Note: in this photo I had the “adjustable flaps” of my universal cross bar on backwards. I needed to turn them around so they were “slidable”