I looked at the Solver Output for #3, the Magnifying the grid system and I see this:
*** FATAL *** CP = 6.203 TIME= 18:01:16
The version size limits( NODES )have been exceeded.
If I look at the Statistics category of the Mesh, I see the number of nodes is 208,024
The Student License has limit on the largest node number in the model and the 2021 R1 version will not solve for models with more that 128,000 nodes.
You need to create a mesh that has fewer than 128,000 nodes.