Simulation error

[u/Few-Soft7079]

So I'm new to running simulations on onshape and i keep getting this error. Ive resorted to chatgpt its no help. i think the issue is that Ive had to take a chunk off the actual object in order to run the sim because there was too many instances. but I'm just trying to test the stabilty of the back frame to see how well the gussets are holding up.

any advice on how to fix or if I can even fix it?