First of all, you must do everything to get moisture out of your house. Make sure you run your bathroom fans for 15-20 minutes after a shower etc. In fact putting a timer on them is a good idea. Make sure your washing machine dryer is venting outside.
If the insulation in the attic is wet, it should all be removed. Then use a mold killer and sealant on the ceiling joists.
Then blow in at least R30-33 in the attic and make sure your ridge vents and soffit vents are working and ventilate above the insulation. This may be your problem. The attic insulation should not cover the soffit venting.
This should cure your problem. Let me know how you do.