warning: V2=0 in GasMixVisc

Hi All!,

What does the following warning means? What may be the cause?

FAILURE IN LINEAR EQUATION SOLVER

warning: V2=0 in GasMixVisc

I run TOUGH3 + ECO2N V2.0 to simulate CO2 injection into fractured geothermal reservoir. The simulation continues until the end, but it takes an extremely long time.

I would be very grateful for any tips.

Best regards,
Maciej