Gummy Skin Chicken Wings

Last night I tried to smoke fry some wings and got a gummy/hard to chew skin. I had them in the smoker for about 90 minutes. They had a good smoke flavor to them. After that I put them in the fryer for about 2 minutes. The taste was amazing, The only negative was the skin was gummy/chewy/not very good. Any ideas how to get the skin crispy? I smoked them at about 225. Was the smoking temp too low? Smoking time too short? Oil not hot enough to crisp the skin? Thanks in advance.