The mod Level Up - Forked (1.1.9) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event levelup-forked::on_nth_tick(6)
LuaEntity API call when LuaEntity was invalid.

stack traceback:

lelvup-forked/control.lua:132: in funtion 'qualityUpgrade'
lelvup-forked/control.lua:156: in funtion 'get_buildings'
lelvup-forked/control.lua:185: in funtion <levelup-forked/control.lua:183>

I was making some test it looks like it crash when I let the machines on the blueprint sandboxes world running and they tried to level up on that world I guees the mods are not compatible at the moment

mod portal:
https://mods.factorio.com/mod/blueprint-sandboxes