Move exceeds maximum extrusion

I am getting the error message "Move exceeds maximum extrusion (0.361mm^2 vs 0.080mm^2)
See the 'max_extrude_cross_section' config option for details"

I have just changed from a 0.6mm nozzle to a 0.25 mm nozzle.

I get this error immediately after printing the prime blob

I have changed the nozzle size in printer.cfg and I have changed the line width in Slicer.
I have reduced the speed to 20% in Mainsail
Not sure what to try next.