The mod Rocket Surgery (0.3.1) caused a non-recoverable error.

Mod conflict with
https://mods.factorio.com/mod/rocket_surgery

This pops up when trying to launch your rocket
I used the shortcut target thingy

I notify the author of that mod also, see on which side the problem is

Error while running event rocket_surgery::on_rocket_launch_ordered (ID 118)
Unknown entity name: liftoff
stack traceback:
[C]: in function 'create_entity'
rocket_surgery/control.lua:5: in function 'make_explosion'
rocket_surgery/control.lua:19: in function <rocket_surgery/control.lua:13>

EDIT:
Works fine without Rocket Surgery,so ill assume it's the other mod that is causing problems