May be you have plotted to a non interactive termial

[kaihendry]

https://s.natalian.org/2020-08-22/gnuplot.mp4

Keep running into this error. Any ideas why? It's breaking the workflow with Gnuplot...

[has2k1]

That is just an inaccurate error message. The real problem is that you had bad gnuplot syntax i.e. title="blah blah" instead of title "blah blah", to which gnuplot complained "invalid expression". What the kernel sees is a plot command, so it prepares an image file for gnuplot to print to; , gnuplot draws nothing because of the bad syntax and the kernel reacts to something wrong but not sure what it is.

I will add this case to what could have gone wrong.