I have laundry out but no water is being collected by my dehumidifier?

If the dehumidifier detects that the RH level is below 35% then it will not operate or collect any water. 

The moisture from your laundry may evaporate into the air and increase the moisture content of the air, but this increase may not be enough to increase the RH level of your room to above 35%. 

This is quite common in winter when the temperature is low and the heating inside the home is switched on.