Use canned air to blow clean the game cart slot reader. Don't use your breath because if spit gets in there, it can corrode metal pins. Try cleaning the flashcart's contacts with rubbing alcohol and q-tip.
If you attempt cleaning the game cart slot with rubbing alcohol, use note card dabbed with the solution. Don't use q-tip as cotton strands can get ripped off and stuck in there. Also, it's better if you remove the 3DS battery while cleaning with the alcohol.
Also, your flashcart has a time bomb. You need the YSMenu kernel to bypass this.
