Problem with solving Maxwell's equations in NGSolve

Hello,

I am using NGSolve to solve Maxwell's equations in a time-harmonic form.
The problem that I work on is B=curl(u) * curl(v)-beta*u*v. I use the first order Nedelec space V for the approximate solution and use an auxiliary subspace W of the Nedelec space (W =span {second order face basis+third order volume basis) for computing the error function "e."

I solve the problem for different choices of the coefficient "beta."
The code produces reasonable results for most of these values, but these results look somewhat erratic for the significant positives values of beta, e.g., {10^(2),10^(4)}. Also, the code fails to produce condition numbers for these specific values of beta. I am not quite familiar with using Preconditioners or Solvers in NGSolve, I tried using different types of them, but this doesn't work. I am not sure which type of them work fine with my problem.

In the attached file Example1.pdf, I show an example and results. And the code is shown in the python script Example1_UniformRef.py.

I am grateful for any explanation or help that handles this problem.

Best regards,

Ahmed El sakori