spyders require a little back pressure to recock. This is usually due to either lower pressure or vlave spring and main spring not keeping valve open long enough to right amount of air in to recock gun. Depending on the situation they may only recock while firing paint or with barrel off and no paint with hand over breach. This works on my 3 lp spyders.
Try these fixes in order.
1. Try finding a main spring guide if u don't have one. You may be able to improvise temporarily. Ive used macroline with a nail inside before and various shims to achieve proper velocity until I could get a new spring guide.
2. Try changeling springs with a spring kit. Light valve spring and medium main spring seems to be the magic combine for me.