CF11 cfc gives 500 error but cfm is fine

Adding a bit more about this solution to the problem, first about Adam's last post, the URL he offered no longer works, but here is the page from the web archive:

http://web.archive.org/web/20150925003635/http://fusiongrokker.com/post/coldfusion-11-sometimes-chokes-on-api

Second, in case it may help others to find this (since his old post no longer shows up in search engines), you can also tell this is happening because you may see an error in your CF application.log (and coldfusion-out.log) about "Application  could not be found", if your request is for a folder called /api  which you have but (as of CF11) CF is looking instead for a REST service registered in the CF Admin or application.cfc and is finding none. Of if you have a subfolder like /api/whatever/ the error might say "application whatever could not be found").

And as Adam's post noted, you could also find more detail on the problem (and the reference to CF's restservlet) in the CF's exception.log.

He proposes one solution is to rename your web site's /api folder to another name (which he acknowledges can have problems), or he shows editing CF's web.xml and comment out its reference to /api if you don't use CF's rest feature.  I'll add a clarification that there are multiple web.xml files in CF: he meant the one in cfusion/wwwroot/WEB-INF/web.xml (of change cfusion to instancename if using CF's multiple instances feature). And I'll add a recommendation that you backup that file before touching it, in case you make a mistake and need to quickly recover.

Finally, as an update, note that CF2018 did change that internal path to instead be /restapps, so folks using /api for  web site folder names would no longer hit this problem. It's only those on CF11 and 2016.