I've got two point features that I am comparing. Both represent physical structures.
The following was my workflow:
1) reprojected features to WGS 84 (4326)
2) I added fields for X and Y values and calculated geometry appropriately
3) joined the first table to the the second
4) Ran XY To Line, and included and ID that was the structure building number
Line Type: Geodesic
XY to Line created the lines, but ALL attributes are <NULL> and the ID field didn't appear.
There were NO errors.
Why are the attributes <NULL>?
Where's my ID field?
Glad it worked out...
I have just gotten into the habit of making joins permanent every time... you can always delete what you don't want after you are done.