Pspice simulation problem

What is a convergence problem? My circuit code is below and when I simulate it is saying that the NMOS transistors MPDA and MPDB are not converging. See the following screenshot:

Here's the netlist:

V1 1 0 DC 5V
V2 2 0 PULSE(0 5 3ns 3ns 3ns 20ns 40ns)
V3 3 0 PULSE(0 5 6ns 3ns 3ns 20ns 40ns)
CL 4 0 0.15PF
MPUA 4 2 1 1 IRF150
MPUB 4 3 1 1 IRF150
MPDA 4 2 5 0 IRF250
MPDB 5 3 0 0 IRF250
.MODEL IRF250 NMOS (level=3 w=4u l=3u vto=1.0 tox=470e-10 nsub=38e14 cj=160e-6
+cjsw=430e-12 mj=0.5 mjsw=0.33 kp=30e-6)
.MODEL IRF150 PMOS (level=3 w=10u l=3u vto=-1.0 tox=470e-10 nsub=8.7e14 cj=100e-6
+cjsw=180e-12 mj=0.5 mjsw=0.33 kp=12e-6)
.TRAN 1ns 80ns
.PROBE V(2,0) V(3,0) V(CL) ID(MPDA) ID(MPUA)
.END

• Did you enter a schematic in the capture program or did you enter your netlist by hand? In the former case a screenshot of the schematic could help. Moreover, post a text version of your netlist, so that we can copy and paste it in our simulation programs instead of copying by hand the netlist in that tiny image. Commented Jun 28, 2015 at 9:22
• @Lorenzo the netlist: V1 1 0 DC 5V V2 2 0 PULSE(0 5 3ns 3ns 3ns 20ns 40ns) V3 3 0 PULSE(0 5 6ns 3ns 3ns 20ns 40ns) CL 4 0 0.15PF MPUA 4 2 1 1 IRF150 MPUB 4 3 1 1 IRF150 MPDA 4 2 5 0 IRF250 MPDB 5 3 0 0 IRF250 .MODEL IRF250 NMOS (level=3 w=4u l=3u vto=1.0 tox=470e-10 nsub=38e14 cj=160e-6 +cjsw=430e-12 mj=0.5 mjsw=0.33 kp=30e-6) .MODEL IRF150 PMOS (level=3 w=10u l=3u vto=-1.0 tox=470e-10 nsub=8.7e14 cj=100e-6 +cjsw=180e-12 mj=0.5 mjsw=0.33 kp=12e-6) .TRAN 1ns 30ns .PROBE V(2,0) V(3,0) V(CL) ID(MPDA) ID(MPUA) .END Commented Jun 28, 2015 at 10:27