Fittings purchased at consumer points such as Home Depot tend to be of three types, but the most popular is "industrial." In the image below,

1. Automotive (type C) is blue
2. Industrial (type D) is red
3. ARO (type B) is green

The fittings even on my more automotive tools such as the air tools I use to work on my car are "industrial" rather than automotive. I have bought automotive over my lifetime always to discover it won't work. I have a few kicking around that continue to disappoint me.