Can't fit a curve for an exponential function, anyone knows why?

Hello,

I mapped out a relation between voltage and resistance on a device and need to fit a curve to this graph, however Excel can not do it although it seems like a pretty standard exp. function to me. Any help will be greatly appreciated. I am also interested in linearising the data later on, I don't know if this this helped at this stage or not. Thanks! File is attached.