'm designing an antenna and the substrate is suppose a material (with 275 um thickness) and the structure on that is in nm range. How to do the meshing?

With automatic meshing(and adaptive meshing) , I'm finding the error that possible stagnation after 250 iterations & automatic solver is stopped. Direct solver will be used.

what to do? Can I rely on automatic solver?

Edu CST Studio ​​​​​​​