The printer skips one page between every print. (CX1000)
The CX1000 is printing the image too long. It stops printing too late for it to see the next black mark so it has to skip one. 1. Try a stretch calibration. See this article.
2. The Black Mark Repeat Length could be set wrong. Check the stock sticker that came with your label stock for the correct setting or measure the distance from the end of one black mark to the beginning of the next. 3. The Vertical Die spacing could be wrong. Check the stock sticker that came with your label stock for the correct setting or measure the distance from the end of one cut to the beginning of the next (with the web).