I'm trying to develop an external form and running into some trouble- I'm sure it's just the PHP I'm trying to use and not a C5 issue, but C5 is suppressing errors so I can't tell what's going on.

When I hit submit on the form it goes to a blank page (as the controller has stopped) instead of returning to the form page.

I have C5 set to Development mode on the Debug panel so other errors are showing, but my custom external form isn't displaying or logging exceptions anywhere.

Any way I can view the exceptions it's throwing?