Severe simulation error

edit

I have been running simulations on my model frequently and all of a sudden a ton of errors have been appearing and the simulation terminates. I don't know what I changed in my DesignBuilder model to cause these errors.

The only severe error is: PsyRhoAirFnPbTdbW: RhoAir (Density of Air) is calculated <= 0 [-0.20088]. pb=[98875.00], tdb=[-1952.78], w=[1.3106801E-002]. Routine=CorrectZoneHumRat, Environment=CWRU (01-01:31-12), at Simulation time=06/29 22:00 - 22:01

Any idea what I need to adjust in my model that would get rid of this error? Thank you!