Hi, You will find typical troubleshooting steps here: https://www.simscale.com/knowledge-base/divergence-simulation-knowledge-base/ In short, look around the region where the divergence took place. There will usually be small faces/gaps in the CAD which cause poor mesh quality locally. The most robust workflow is to clean up the CAD model, removing these details. In some (rare) cases, adding mesh refinement helps.