1D FDEM reciever location problem

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Hello, I’m new to simpeg, maybe someone can give me an advice on following topic:

I want to use it for 1D FDEM Forward Simulation. The assumption is that the source is on the ground and the receiver is in the air. I set them as follows:
source_location = np.array([0.0, 0.0, 1.0])
receiver_locations = np.array([0.0, 0.0, 30.0])

In this case, code execution results in an error. In case I change the X coordinate of the receiver to non-zero the code works as it should, so I think this is the problem.

Here is my full code:

import simpeg.electromagnetics.frequency_domain as fdem
from simpeg import maps
from simpeg.utils import plot_1d_layer_model
import os
import numpy as np
from scipy.constants import mu_0
import matplotlib as mpl
import matplotlib.pyplot as plt

currentinsquare = 1 #A
s_of_square = 10**6 #sq m
rho_kimb = 100 #om*m
rho_trapp = 4000 #om*m
rho_limestone = 1000 #om*m

frequencies = np.array([19.53, 78.12,312.5])
source_location = np.array([0.0, 0.0, 1.0])
source_orientation = "z" 
moment = currentinsquare*s_of_square

receiver_locations = np.array([0.0, 0.0, 1.0])
receiver_orientation = "z" 
data_type = "ppm"

source_list = [] 

for freq in frequencies:
    receiver_list = []
    receiver_list.append(
        fdem.receivers.PointMagneticFieldSecondary(
            receiver_locations,
            orientation=receiver_orientation,
            data_type=data_type,
            component="real",
        )
    )

    source_list.append(
        fdem.sources.MagDipole(
            receiver_list=receiver_list,
            frequency=freq,
            location=source_location,
            orientation=source_orientation,
            moment=moment,
        )
    )

survey = fdem.survey.Survey(source_list)

layer_thicknesses = np.array([100.0])

layer_conductivities = np.array([rho_trapp**(-1), rho_kimb**(-1)])

n_layers = len(layer_conductivities)

conductivity_model = layer_conductivities.copy()

conductivity_map = maps.IdentityMap()

simulation_conductivity = fdem.Simulation1DLayered(
    survey=survey,
    thicknesses=layer_thicknesses,
    sigmaMap=conductivity_map,
)

dpred_conductivity = simulation_conductivity.dpred(conductivity_model)

print(dpred_conductivity)

Thanks in advance