Why won my Pokemon evolve?
If your Pokemon evolves into either a GSC or RS Pokemon, then it won’t evolve until you receive the National Dex, and fix the Pokemon Network on One Island. To get the National Dex, you must first beat the Elite Four, and catch 60 Pokemon. The go give Professor Oak a visit in Pallet Town and he will give it to you. For more information on fixing the Pokemon Network, check out the Islands Walkthrough.