I am having difficulties in joining 2 tables using a defined-field (MRE 7.1.1).
I created a defined-field using "Field Selection" tab.
And then, using the "Join Options" tab, I select my defined-field created before and join it with one of my indexes of my second table.
It generates a "valid" code.
But when I go back to "Field Selection" tab to add a field from my second table into my report, and then I run the report, I get the error message below:
"Unknown error occurred.
ERROR: "
Am I doing something wrong?

I figured out the issue:
I was using "Unspecified" join type. After I changed it to "Left Outer", I got the results I was looking for.