spopt: pulp.apis.core.PulpSolverError: Pulp: cannot execute cbc.exe

Hello,

I am trying to execute the following:

solver = pulp.COIN_CMD(msg=True, warmStart=True)

pcenter_from_cm = PCenter.from_cost_matrix(
    distances, p_facilities=facilities, name="p-center-network-distance"
)

pcenter_from_cm = pcenter_from_cm.solve(solver)

But get the following error:

pcenter_from_cm = pcenter_from_cm.solve(solver)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\x\Documents\spopt_venv\lib\site-packages\spopt\locate\p_center.py", line 409, in solve
    self.problem.solve(solver)
  File "C:\Users\x\Documents\spopt_venv\lib\site-packages\pulp\pulp.py", line 1913, in solve
    status = solver.actualSolve(self, **kwargs)
  File "C:\Users\x\Documents\spopt_venv\lib\site-packages\pulp\apis\coin_api.py", line 137, in actualSolve
    return self.solve_CBC(lp, **kwargs)
  File "C:\Users\x\Documents\spopt_venv\lib\site-packages\pulp\apis\coin_api.py", line 146, in solve_CBC
    raise PulpSolverError(
pulp.apis.core.PulpSolverError: Pulp: cannot execute cbc.exe cwd: C:\Users\x\Documents\

Does anybody have any suggestions?

I have tried passing the msg=1 argument to the solver, to get more information.

I have checked the precision of the numbers, rounding them.

The cost distance matrix is is a pairwise distance matrix of one df of points - i.e. with itself. Could it be that it is due to duplicated variables / constraints?