Accuracy decreasing after optimize_for_mobile

Mobile
#1 

traced_script_module_optimized = optimize_for_mobile(traced_script_module)```

The traced_script_module gives an accuracy of 98% but for optimised one the accuracy falls down to 6%. How can I overcome this?
#2

Is it a quantized model? cc: @kimishpatel

#3

Yes. The model was dynamically quantized then optimised