[Python] ValueError: The model function generated NaN values and the fit aborted! showing up...

I am trying to fit a custom function, which involves a set lower incomplete gamma function, to a set of data I have using lmfit. I additionally want to impose a constraint on my parameters given by the equation ((A*m**k)/k)-B=1. I keep getting an error, saying it doesn't work.

Please help I do not know what I am doing.

Here is my code including the data.

import numpy as np
import sympy as sy
import matplotlib.pyplot as plt
from lmfit import Model
from lmfit import Parameters
from sympy.parsing import sympy_parser
#%%
xdata = [0.01, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420, 450, 480, 510, 540, 570, 600]
ydata = [1, 1.081070134, 1.123434136, 1.163246076, 1.180650102, 1.198810838, 1.20990884, 1.218026926, 1.221569822, 1.228107416, 1.223498562, 1.232861926, 1.23392966, 1.222959988, 1.21195955, 1.195828866, 1.174534424, 1.153189058, 1.136328876, 1.121319582, 1.100934304, 1.07886202, 1.073743626, 1.053117992, 1.035234418, 1.016680182, 1.002735456, 0.993092576, 0.97627191, 0.971622838, 0.94703108]
#%%
gamma = sympy_parser.parse_expr('A*lowergamma(k,m*t)/(t**k)')
sf = sympy_parser.parse_expr('-1*B*exp(-q*t)')
model_list = sy.Array((gamma, sf))
model = sum(model_list)

model_list_func = sy.lambdify(list(model_list.free_symbols), model_list)
model_func = sy.lambdify(list(model.free_symbols), model)

lm_mod = Model(model_func)
print(f'parameter names: {lm_mod.param_names}')
print(f'independent variables: {lm_mod.independent_vars}')

params = lm_mod.make_params(B=dict(value=1,min=0,max=15), k=dict(value=7.2E-1,min=0),
A=dict(value=.5,min=0,max=50), q=dict(value=1.31E-2,min=0), m=dict(value=1.31E-2,min=0))
params.add('constraint_1',expr='((A*m**k)/k)-B',min=.9,max=1.1)

res = lm_mod.fit(PLt[1], params=params, t=PLt[0])

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