Slow Cooker Cake

I found a recipe that looked promising for a slow cooker cake, just a regular degular chocolate cake. The recipe said it takes 2hrs on high, however, mine has taken nearly over 8 and is still mega goopy inside?! Anyone have any idea as to why...or how? I followed the recipe exactly bar using a tea towel to cover rather than paper towel cos i dont have any 🤷‍♂️