Simulating circuit on PSPICE Convergence error

I'm trying to simulate an one bit ADC using only mosfet transistors but keeps giving me an convergence error

The model info for each of the transistors are 

.model MbreakP PMOS LEVEL 3
+ TOX = 9E-9 COX = 3.8E-15 GAMMA = 0
+ LAMBDA = 0.1 CGDO = 500E-12 CGSO = 500E-12
+ VTO =-0.8 KP=68E-6 COX=3.8E-15

.model MbreakN NMOS LEVEL = 3
+ TOX = 9E-9 COX = 3.8E-15 GAMMA = 0
+ LAMBDA = 0.1 CGDO = 500E-12 CGSO = 500E-12
+ VTO =0.7 KP=190E-6 COX=3.8E-15

Here are the screenshot of the PSPICE error and the design circuit

drive.google.com/open

Can anyone pinpoint what exactly is wrong here? Thank you