Error occurs when calculating sub-GeV dark matter

when I calculate the process chi chi~ > e+ e- for the effective operator " Gf chibarchi fbarf" , when I set the dark matter mass to 100MeV, the result of maddm is:
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################################################
# MadDM v. 3.2 #
################################################

################################################
# Relic Density #
################################################

Omegah2 = 6.57e+00
Omegah_Planck = 1.20e-01
xsi = 1.00e+00 # xsi = (Omega/Omega_Planck)
x_f = 1.00e+01
sigmav_xf = 3.71e-28 # cm^3 s^-1
# % of the relic density channels
%_xchixchix_ssx = 0.00 %
%_xchixchix_emep = 100.00 %
%_xchixchix_uux = 0.00 %
%_xchixchix_vtvtx = 0.00 %
%_xchixchix_ccx = 0.00 %
%_xchixchix_ttx = 0.00 %
%_xchixchix_mummup = 0.00 %
%_xchixchix_vevex = 0.00 %
%_xchixchix_ddx = 0.00 %
%_xchixchix_bbx = 0.00 %
%_xchixchix_vmvmx = 0.00 %
%_xchixchix_tamtap = 0.00 %

################################################
# Indirect Detection #
################################################
# Results in brackets display [prediction, upper limit]

# Annihilation cross section computed with the method: madevent
# <sigma v>[cm^3 s^-1] of continuum spectrum final states and Fermi dSph limits (if available, else -1)
xchixchix_ddx = [0.00e+00,-1.00e+00]
xchixchix_ttx = [0.00e+00,-1.00e+00]
xchixchix_vlvl = [0.00e+00,-1.00e+00]
xchixchix_ll = [3.21e-36,-1.00e+00]
xchixchix_bbx = [0.00e+00,-1.00e+00]
xchixchix_ccx = [0.00e+00,-1.00e+00]
xchixchix_ssx = [0.00e+00,-1.00e+00]
xchixchix_tamtap = [0.00e+00,-1.00e+00]
xchixchix_uux = [0.00e+00,-1.00e+00]

# Global Fermi dSph Limit computed with pythia8 spectra
Total_xsec = [3.21e-36,-1.00e+00]
Fermi_Likelihood = -1.76e+01
Fermi_pvalue = 0.00e+00

#################################################
# CR Flux at Earth [particles cm^-2 s^-1 sr^-1) #
#################################################

# Fluxes calculated using the spectra from dragon

Flux_neutrinos_e = nan
Flux_neutrinos_mu = nan
Flux_neutrinos_tau = nan
Flux_gammas = nan
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It can be seen that there is a problem with the output energy spectrum, showing "nan".

At the same time, madevent also shows an error：
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<MGGenerationInfo>
# Number of Events : 100000
# Integrated weight (pb) : 69.298
</MGGenerationInfo>
<MGGenerationInfo>
# Number of Events : 100000
# Integrated weight (pb) : 3.0968e-06
</MGGenerationInfo>
</header>
<init>
52 52 5.000000e+02 5.000000e+02 0 0 0 0 -4 1
3.096800e-06 1.325700e-09 3.096800e-06 1995
<generator name='MadGraph5_aMC@NLO' version='3.3.2'>please cite 1405.0301 </generator>
</init>
<event>
 4 1995 +3.0968000e-06 2.00000000e-01 7.81860800e-03 nan
  9100001 -1 0 0 0 0 +0.0000000000e+00 +0.0000000000e+00 +1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00
 -9100001 -1 0 0 0 0 -0.0000000000e+00 -0.0000000000e+00 -1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00
       11 1 1 2 0 0 -8.5974541474e-02 +2.8951572333e-02 -4.2073562742e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 1.0000e+00
      -11 1 1 2 0 0 +8.5974541474e-02 -2.8951572333e-02 +4.2073562742e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 1.0000e+00
</event>
<event>
 4 1995 +3.0968000e-06 2.00000000e-01 7.81860800e-03 nan
  9100001 -1 0 0 0 0 +0.0000000000e+00 +0.0000000000e+00 +1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00
 -9100001 -1 0 0 0 0 -0.0000000000e+00 -0.0000000000e+00 -1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00
       11 1 1 2 0 0 -8.7280464371e-02 +3.3613981069e-02 +3.5386732257e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 -1.0000e+00
      -11 1 1 2 0 0 +8.7280464371e-02 -3.3613981069e-02 -3.5386732257e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 -1.0000e+00
</event>
......
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You can see that "nan" appears in the event.

So of course pythia8 will also get errors:
——————————————————————————————————————————————————————————
 *------- PYTHIA Error and Warning Messages Statistics ----------------------------------------------------------*
 | |
 | times message |
 | |
 | 10 Abort from Pythia::next: reached end of Les Houches Events File |
 | 1 Info from SLHAinterface::initSLHA: No MODSEL found, keeping internal SUSY switched off |
 | 1 Info from SLHAinterface::initSLHA: importing MASS entries |
 | 1 Warning in SLHAinterface::initSLHA: ignoring DECAY tables |
 | 1 Warning in SLHAinterface::initSLHA: ignoring MASS entries |
 | 1 Warning in SLHAinterface::initSLHA: ignoring empty DECAY tables |
 | 1 Warning in SLHAinterface::initSLHA: massless particle forced stable |
 | |
 *------- End PYTHIA Error and Warning Messages Statistics ------------------------------------------------------*
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I would like to know how to solve this problem, or whether MadDM is suitable for sub-GeV dark matter mass calculations.