Error with small pyomo optimization problem

[yonizim]

Hello,

I stumbled upon a small optimization problem which may cause trouble to couenne optimizer. I'm working with pyomo 6.0.1, MacOSX 12.1 and couenne 0.5.7.

Here it the example:

import itertools
import pyomo.environ as pyo
from pyomo.opt import SolverFactory

m = pyo.ConcreteModel()

idx = itertools.product([0, 1], repeat=2)
m.x = pyo.Var(idx, domain=pyo.Binary)

m.a1 = pyo.Constraint(expr=m.x[0, 0] + m.x[0, 1] == 1)
m.a2 = pyo.Constraint(expr=m.x[1, 0] + m.x[1, 1] == 1)
m.a3 = pyo.Constraint(expr=m.x[0, 0] + m.x[1, 0] == 1)
m.a4 = pyo.Constraint(expr=m.x[0, 1] + m.x[1, 1] == 1)
m.c = pyo.Objective(expr=m.x[0, 0] * m.x[1, 1] + m.x[0, 1] * m.x[1, 0])

solver.solve(SolverFactory("couenne"))

In return, I get:

raise ApplicationError(pyomo.common.errors.ApplicationError: Solver (asl) did not exit normally

BTW, other similar problems are solved correctly without any errors.

I will be glad to get any direction for the possible reason for this behaviour.

Thanks.