I am trying a simulation in Fluidity/ICFERST for 3D geometry generated from Gmsh. It is giving me these error messages

WARNING: Failed to converge.
PETSc did not converge for matrix solve of: DeltaP
Reason for non-convergence: KSP_DIVERGED_NAN
Number of iterations: 0
Specified ignore_all_solver_failures, therefore continuing
Dumping matrix equation in file called matrixdump.

When I ran it in 2D, it ran successfully without any problem. Does anyone know the solution to this error please?

This is a FreeFEM board, PETSc-specific questions should be sent to either petsc-users@mcs.anl.gov or petsc-maint@mcs.anl.gov. Thank you for understanding.