Resolved issue, I think. OBi Line 1 was split to phone and house line, OBi Line 2 was connected directly to phone [line 2]. If Line 1 was connected to house line, Line 2 was not available. If Line 1 was not connected to house line, Line 2 was available. I connected the line going to the house line to a splitter that had a dedicated " Line 1" port and then Line 2 worked. Since Line 2 had no connection to Line 1 or the house line, the only commonality/connection was the OBi unit. Apparently the OBi unit did not like the original setup.
This "fix" would make more sense if Line 2 was also connected to the house line thru the new splitter using a dedicated "Line 2" port. Then I could see the new splitter having this effect. But not when the 2 lines were not connected, other than their origin [OBi unit].
Main telephone "line 2" wires are not connected at the junction box outside house. This confuses me more as that should lessen any conflict, I would think.
What was the problem so I can avoid issues in the future.