Android : why my android service crashes?

This is my first need of help, sorry for that. I dont undersand why my android service crashes. here is what i do : - a start an application that on a button click i start a sticky service by "startService" (it works for hours whitout any problem) - i stop the same service by "stopService" with i think all the cleanup necessary ? i hope so in fact - when i restart it with same start button ..... application immediatly crahes .... but the service itself restarts and work well ..... Could you give me somme advises on what could be wrong ? thanks