Unable to use jupyter with the solver

Dear everyone!
I am using NGSolve-6.2.1809 (since I have Mac OS Sierra) with python 3.7.7. I am trying to run poisson.ipynb tutorial but I am getting this error:

TclError: dlopen(/Applications/Netgen.app/Contents/MacOS/libgui.dylib, 6): Symbol not found: _NSZeroRect
Referenced from: /Applications/Netgen.app/Contents/MacOS/libgui.dylib
Expected in: flat namespace
in /Applications/Netgen.app/Contents/MacOS/libgui.dylib

Please help me out fix this. I don’t know what the problem is.

Thank you.