Information for both layers is sent to the server in the request json, but the feature layers do not appear in the resulting file. The graphics layers render just fine.
I've tried submitting the json from API interface on the server, with the server URl and with locahost, https and http. I get the same results. There's no indication of an error and I can find no logs that indicate a problem.
I suspect the issue is on the server, my client code is very simple and the layer is in the json request. Could it be something to do with how the feature layer is defined on the server?
This is difficult to troubleshoot without additional information. What version of the JS API are you using? What is the version of ArcGIS Server that hosts the layers? Where is the print service (is it AGO utility or on the same server that is hosting the layers)?