I have come across a glitch in JMRI that seems to be tripping up a lot of people. It happens at random times even after you have been using it just fine. Can also happen when you install and setup JMRI for the first time but with NO HARDWARE connected.
What happens it that since JMRI sees no hardware it sets your connection defaults to "Internal" This setting is for testing JMRI WITHOUT HARDWARE.
This setting can also get changed randomly even after you have JMRI installed and running ok.
Bottom line of Decoder Pro window should look like this:
If it says "Internal" instead of "NCE" That is incorrect!
Fortunately, it is very simple to check and fix.
From the regular Decoder Pro All Entries screen go to: Edit / Preferences / Defaults.
all of the selections MUST BE set to NCE not internal. correct them as needed then click save.
exit out of JMRI, close out everything running, and reboot your PC. Also power cycle / reboot your NCE equipment.
That's it! Let me know if this works.