Error 500 when adding new expression

Hi there,
I’m having a bit of an issue with my query section.
When I try to add a new expression, I get an error 500 straight away, even though I haven’t written anything in the expression field.
I’ve looked in the transformation section, but there’s nothing there that matches.
Any advice would be greatly appreciated! I’m hoping someone can help me with a little problem I’m having.
I’m trying to do a calculation, but I’m getting an error.
The calculation is: (1152-$C)*5+(1152-$C)*0.133.
I’m using the http API infinity, and my Grafana version is the most recent. the funny thong is i already got the problem solved in another panel, even though i use the same query…

Compare panel json models of working panel with broken panel and fix differencess directly in the panel json model.