I would love some help with thickening, if someone has a moment. I am trying to complete a practice exercise for creating an AirPod. I've reached the point when I need to thicken, but it keeps failing, while it appears to have worked fine in the tutorial. While the thicken amount prescribed in the tutorial is 0.25 mm, I checked the Minimum radius of Curvature (0.056864 mm), which I think it may be the problem---it appears to be located in the inside "underbelly" near the stem.

Alternatively, I tried (in a different file), to instead temporarily fill all the openings with surfaces and go back before the knit and re-do it with a KNIT & create a solid. This worked but then shelling to 0.25 mm failed.

I've provided images, SW part file in zip folder, and the link to tutorial below.) Thanks!  

https://learnsolidworks.com/solidworks_tutorials/model-apples-airpods-solidworks  

​​​​​​​​​​​​​​