It absolutely is. Especially when it "doesn't work" (not configured correctly.) Can someone look at a browser log and figure out what's going on? It's not just a front end issue, either. I've seen backend engineers set up crazy CORS configurations for internal APIs that would've been better served with a proxy off of a single origin. I even ran into an "architect level" guy that had no understanding of how that would even work. "You can POST without CORS???" seriously...