Octolapse won't take snapshots


I have installed Octolapse (latest revision) and configured all of the variables (I think). When I start a print Octolapse indicates that it is running, but no snapshots are taken.
My printer is a Creality CR-10 that has been running very well on Octoprint with a Raspberry Pi. The video camera is a generic type but does show a good picture when the "CONTROL" tab is selected. The trigger point is set to "LAYER CHANGE". I have tried to get a log report, but nothing is recorded.
What did you already try to solve it?
Does someone have any suggestions?