SPICE simulation of voltage multiplier using log and antilog amplifier
The problem is that to get 1 V across the diode (D10?) requires about 2 A through it. And 2 A through the 10 kohm feedback resistor R11 would require 20 kV at the output of the final stage amplifier. (And of course in the real world these voltages and currents would quickly burn out these devices)

So you want to reduce the gain of the preceding stages.

You can't do that by just blindly increasing all resistor values. You have to adjust them appropriately to lower the gain. That would mean doing one or more of:


Lower R7 or R12
Increase R13
Increase R8 and R9
Increase R2 and R6


(Or, to get your simulation working, use much lower input values, like 0.5 and 0.2 V)