The error message is generic and suggests unknown issues with analysis setup. If possible, please share the .pmx file. You can use some hosting website and paste the link here.
What load do you apply in this model ? Can you share a screenshot with it or a .pmx file where it’s defined ? The Word document only mentions a boundary condition, not load.
Is that a failed attempt to share the file directly here ?
Anyway, it seems that you applied this concentrated force to the edge. Here’s an explanation why it shouldn’t be used on surfaces in most cases: Don't apply concentrated force load to surfaces but it applies to edges as well if you don’t want the specified magnitude to be applied to each node (so the total load is specified magnitude*number of nodes).
Ok, I have it now. There are errors about negative jacobians because of the thin top parts of the flanges. One has particularly nasty and maybe even faulty geometry: