I just went through this issue too. For me the problem got so bad that I was completely unable to open the door from the outside. Yet, the inside door handle opened the door easily. If you cannot open the door from the inside, then our problems are quite different, I suspect. As the problem worsened last Fall (got it fixed I thought at Canyonville) and again over the Winter (got it fixed again I thought at BCS in April), I found pushing hard inward on the door, then pulling the opener would allow it to work for me. But for my S.O., she was unable to open the door. I finally found the problem here at home. It was the lower hinge on the outside door handle. The plastic hinge had broken out. I called BCS and got a new exterior door handle and put it in. Now it works like a new door. All the other door opener parts are okay. I replaced only the mechanism that includes the outside door handle.
By the way - leave a window unlocked JUST IN CASE you are completely unable to get the door open. I'm glad I did. At least we could gain entry through the window over the couch to open the door from the inside.