In case you're faced with a technical error screen in C4C and are looking for the root cause:
- Don't close the error screen. Click "Report Incident" instead.
- Open the Incident from the Administrator Work Center
- Find the section "Incident Context"
- Click on /SAP/ABAP/RuntimeError
This will download a zip file that contains an XML file with a name like $SAP$ABAP$RuntimeError.3.xml. Unzip the ZIP and open the XML file in an advanced editor like Notepad++.
You have to use an XML plugin to prettify the XML as it's all on one line.
Once you have done that, you can browse the file and check for the error source. I can't explain you how to do that as it depends on the error, but it's usually in the ApplicationInfo section. Plus, you get a pretty good insight on how C4C works internally.
Here's an example where an incorrectly configured action in the UI designer raised an exception:
If you don't find the solution, forward the incident to SAP. This will pass along the Incident Context. Looking at the incident context is the first thing SAP First Level support do, so you can spare you the trouble by looking at it yourself to see if you can find anything.
As you can see above, there are a number of other files. I haven't been able to find anything useful in them, but then again, I'm not a frontend developer and in case I'm facing a frontend issue, I'm using the Chrome DevTools. So the only useful file is the ABAP runtime error, really.