JoSIM®-Pro reports that the matrix has no solution

Isolate the cause

1. Read the first diagnostic and reduce the netlist to the smallest circuit that reproduces it.
2. Check the intended reference node and floating subcircuits or inconsistent ideal-source constraints.
3. Verify units, model parameters, coupled-inductor validity, bias and initial conditions.
4. Restore parts of the circuit in small steps and compare against a supplied working example.

Preserve the physical circuit

Do not add an arbitrary resistor solely to suppress the message. A corrected circuit resolved a historical zero-resistance-loop report without the proposed artificial resistance.

A weak reference or finite impedance may be physically appropriate for some models, but it changes the circuit. Document and validate that choice rather than treating it as a universal solver repair.