Motherboard stuck in my case

Parts:

https://pcpartpicker.com/list/b4mVfv#compatibility\_notes

I'm having trouble taking my motherboard out of my pc. I have made sure any visible screws are removed, and no cables are plugged in. It feels like it is still screwed in somewhere in the center, but I'm confident there isn't anything to unscrew. I have no idea if the IO is stuck or if it's a common issue with those standoffs for the screws. I'm so nervous about being too forceful and breaking my pc.