I‚’m sorry to hear that this didn‚’t turn out for you. I have a couple of suggestions that might help. The first is to cut the marinating time in half. The other is to omit the yogurt from the marinade in step 6. If you do that, you can add about 100 g of yogurt to the reserved marinade in step 19.
In Step 15, remove the chicken from teh marinade, and make sure to wipe the marinade off the meat with a paper towel before continuing on to the next steps.
Two important steps to follow are to make sure that you cook the chicken to their core temperatures. The breasts should be cooked at 60 C for about an hour, or until the core temperature reaches 60 C, and the thighs should be cooked at 65 C for 1.5 hours, or until they reach 65 C.