problem about VOF and species couple
 

I seted up a case to solve the condensation and evaporation in air. I used VOF and species model together. But when I iterated unsteady for some time step, there was always a error. It was

> "# Divergence detected in AMG solver: gas-species-1 -> Increasing
> relaxation sweeps!
>
> Error: Divergence detected in AMG solver: gas-species-1
>
> Error: Divergence detected in AMG solver: gas-species-1
> Error Object: #f"
>
>


I studied the error for a long time and found when VOF and species coupled, this error will exist even there was not mass transfer. I thought when the cell VOF of liquid decrease from 1.0, the mass fraction of species would cause error. Beacuse when the cell VOF equal to 1.0, the mass fraction of species all eaqual to 0.0 in this cell in fluent. And when this cell's VOF is decreased, the mass fraction of species all increased from 0.0 and perhase this will cause error.

Did someone use VOF and species model together? And did you meet this error? And how to solve this problem?
Pleeeeeeeeeeeeeeeeeeese help me! Thank you!