I unscrewed and screwed back the barrel very carefully. However, the tilting problem in the right lens is still there. As this point, i adjusted the right setscrew and was able to connect the left tip of a horizontal line (roof top) in the right barrel, to the right tip of the horizontal line in the left barrel. The line is not straight because of the problem mentioned above. The right half of the line is tilted downward.
-------------------- Barska X-Trail 15x70, Jason Empire Mercury 10x50, china-brand 15x60