Polymer viscosity model about Cross-WLF eqaution

Hello,

I have tried to analyze the filling pattern of polymers in injection molding process with COMSOL software.
And I tried to apply the shear viscosity of the polymer to the analysis using cross-WLF equation which usually used to express the behaviors.

However, I found out that the viscosity rapidly increased when the temperature of the polymer reached glass transition temperature.
With the increasing viscosity, the analysis was failed.

I need your help with the problem.
Please let me know how I can fix the problem without the fail message.

Best regards,