Help with understanding non-convergence?

I'm using tutorial OS-T 1394 and 1560 (V2022.1) and made a similar model from scratch to check if I understand it. Hopefully someone is willing to help with understanding a non-convergence problem?
Attached is the model, the purpose is to simulate contact between a sphere and wall (axisymmetric).
There is a very good blog post which helped me a lot:
https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4
Thanks to the blog post I could already try the below corrections to solve it:
- Following advice found in output file, friction has been set to zero.
- Contact stabilisation: CNTSTB with parameters from OS-T 1560. Goal is to find stress fields, impact on energy accuracy can be accepted?
- Tried increasing force
- LS input DLOAD - This seems to solve warning 1955 "zero static force vector"?
- It gives info 4936: suggested TLOAD1/TLOAD2. Indeed works fine but does not solve the issue.
- It does seem to solve error 1996: "All entries have zero scale"
- Error 941 now remains: non-convergent iterations
Possible reasons that I can think of:
- Force 0.2N not properly applied?
- Not properly constrained?
- Insufficient/poor elements for the wall part?
- LGDISP needed to capture deformation?
- Convergence expert keeps backing off, but why? Step too large?
Important warnings that remained:
WARNING # 3400 - Singularity detected at following 1 DOFs.
WARNING # 6529 - The x-displacements of grids (e.g., GRID 1) on the axis of symmetry need to be constrained ->
Many thanks in advance!
- Wesley