Summary

The Octoprint plugin DisplayLayerProgress has been changed. I was getting an error everytime I printed. I found that I needed to supply the layer number in my Gcode.
I use PrusaSlicer and found this works.
Enter this in the before layer section
;LAYER:[layer_num]
See screen shot
I no longer use CURA, so not sure how to make it work in CURA.
Here is a link to the plug in
https://github.com/OllisGit/OctoPrint-DisplayLayerProgresshttps://github.com/OllisGit/OctoPrint-DisplayLayerProgress