Cura requires a short script being added to the begging of your Start G-Code, in order to make these values available for the automatic slicer configuration to work.
I had this same problem with the Crealty slicer (Cura). I resolved my problem by replacing it with the latest Prusa slicer. I found that it has a lot of nice features that I needed anyway and it worked perfectly.
I had the same issue, using Cura 4.13.1 and OctoPrint 1.7.3. Actually, in my case, it does not have to do with OctoLapse or OctoPrint, well, at some extend, it is OctoLapse.
I do have a post-processing script enabled to generate a thumbnail of the model in the gCode, so I can see it in OctoPrint. When Cura adds the code of the thumbnail to the gCode, it adds it BEFORE the code for OctoLapse, so when I used 600x600 resolution for my thumbnail, OctoLapse code gets moved long after line 1000 (OctoLapse checks for its code in the first 1000 lines of the gCode, if it does not find it, it fails).
Setting the thumbnail to 300x300 let the OctoLapse code to be inside the 1000 first lines of the gCode.
So, 2 things here:
Check your printer settings in Cura, make sure you do have the start script for OctoLapse in the Start G-code for your printer
Make sure your post-processing scripts are not interfering with those settings in the gCode. Open the gCode file and look for the line number of the OctoLapse script, it should be in or before line 1000
There are configs to be added in Cura's printer's Start G-code for OctoLapse auto config.
Everything worked fine for me until I installed ArcWelder.
The ArcWelder plugin was deleting the comments with variables for OctoLapse auto config.