Octolapse Rendering Failed

Octolapse had been working fine, even after I obliterated and performed a clean install of Octoprint. Then one day not long after the reinstall it stopped rendering. It gives the error below, even when I try to render after-the-fact. I am running Octolapse 0.4.1 and I have tried uninstalling and reinstalling the plugin, keeping none of the settings.

Octolapse Rendering Failed
Rendering failed for camera 'Webcam - Default OctoPi 0.16.0', render-error: Unknown render error. Please check plugin_octolapse.log for more details. Inner exception: unsupported format character '_' (0x5f) at index 43

I haven't checked the suggested log file because I don't know exactly where to find it.