Is there any alternative, if the z probe (Proximity sensor) not working then I can use microswitch as Endstop and run the printer now and later I can change to Bltouch
what need to be changed in the config and wiring for microswitch

Thanks droftarts,
I'll correct as suggested,
Heater pin, I was using Bltouch earlier, it was connected to the heater Pin,later changed to proximity sensor (P5)
It was working fine till the time the board change took place, once updated to the latest firmware, had lot disconnection issue then switch over to the previous version, then the z Probe stopped working
Z probe reading on DWC o constant, the sensor led comes up once expose to metal which means the sensor working fine but duet not reading the signal (Signal wire connected to Duet probe IN)
Is there any glare of error in config.g
I've changed the probe twice thought that the sensor could be the issue, but that might not be the problem

After board change and firmware update, the Z probe stopped working, using inductive sensor
1.Sensor's LED comes up once expose to metal
2. changed the probe, even then no luck

what could be the issue, sharing the config.g and file below
My config.g
; Configuration file for Duet WiFi (firmware version 2.03)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v2.0.3 on Tue Sep 10 2019 18:28:37 GMT+0530 (IST)

; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"BIG FACTORY" ; set printer name

; Network
M551 P"3m3d" ; set password
M552 S1 ; enable network
M587 S"MMM" P"KINGS1234" " ; Configure access point. You can delete this line once connected
M587 S"ESYA" P"ESYA@700"
M586 P0 S1 ; enable HTTP
M586 P1 S1 ; enable FTP
M586 P2 S1 ; enable Telnet
M584 X5 Y6 Z7 U11 E3:4 ; create the U axis and assign stepper driver 11 to it
; Drives
M569 P5 S1 ; physical drive 5 goes forwards
M569 P6 S1
M569 P5 R1 T10:10:20:100 ; physical drive 5 goes forwards
M569 P6 R1 T10:10:20:100 ; Physical drive 6 goes forwards
M569 P7 S1 ; physical drive 7 goes forwards
M569 P7 R1 T2.2:2.2:4:20 ; Physical drive 7 goes forwards
M569 P3 S0 ; physical drive 3 goes forwards
M569 P4 S0 ; physical drive 4 goes forwards
M569 P10 S1
M569 P10 R1 T10:10:20:100 ; Physical drive 11 goes forwards
M584 X5 Y6 Z7 U10 E3:4 ; Apply custom drive mapping
M350 X32 Y32 Z32 U32 E32:32 I0 ; Configure microstepping without interpolation
M92 X25 Y16.00 Z10000.00 U25.00 E820.00:820.00 ; Set steps per mm
M566 X1000.00 Y100.00 Z100.00 U1000.00 E120.00:120.00 ; Set maximum instantaneous speed changes (mm/min)
M203 X7000.00 Y7000.00 Z100.00 U7000.00 E1200.00:1200.00 ; Set maximum speeds (mm/min)
M201 X700.00 Y700.00 Z100.00 U700.00 E250.00:250.00 ; Set accelerations (mm/s^2)
M906 X800.00 Y800.00 Z800.00 U800.00 E900.00:800.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
;Filament size
M200 D1.75
; Axis Limits
M208 X1600 Y1100 U1600 Z1700 ; Set axis maxima
M208 X-50 Y0 U0 Z-0.2 S1 ; Set axis minimum (adjust to make X=0 and Y=0 the edge of the bed)

; Endstops
M574 X1 Y1 Z0 U2 S1 ; Set endstop configuration (X and Y endstops at low end, U endstop at high end, active high, no Z endstop)
; Z-Probe
M574 Z1 S2 ; set endstops controlled by probe
M307 H7 A-1 C-1 D-1 ; disable heater on PWM channel for BLTouch
M558 P5 H5 F130 T6000 I1 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X0 Y0 Z1.55 ; set Z probe trigger value, offset and trigger height
M557 X20:1500 Y20:1000 S300 ; define mesh grid

; Heaters
;M141 H4 ; assign chamber heater to heater 0
M305 P0 T100000 B4138 R4700 ; set thermistor + ADC parameters for heater 0
M143 H0 S120 ; set temperature limit for heater 0 to 120C
M305 P1 T100000 B4725 R4700 ; configure PT100 for heater 1
M143 H1 S280 ; set temperature limit for heater 1 to 500C
M305 P2 X201 ; configure PT100 for heater 2
M143 H2 S500 ; set temperature limit for heater 2 to 500C
M305 P4 X202 ; configure PT100 for heater 4
;M143 H4 S120 ; set temperature limit for heater 4 to 120C

; Fans

M106 P0 S0 I0 F500 H T45 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H2 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on
; Tools
M563 P0 S"FIRST" D0 H1 F0 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C
M563 P1 S"SECOND" D1 H2 X3 F2 ; Define tool 1
G10 P1 Y0 U0 Z0 S0 R0 ; set tool 1 offsets and temperatures
M563 P2 S"MIXED" D0:1 H1:2 X0:3 F0:2 ; tool 2 uses both extruders, hot end heaters and fans, and maps X to both X and U

G10 P2 X0 Y0 Z0 ; Set tool 2 axis offsets
G10 P2 X500 Y0 U-500 S0 R0 ; set tool offsets and temperatures
M567 P2 E1:1 ; set mix ratio 100% on both extruders

; Automatic power saving
M911 S19.8 R22 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

; Custom settings are not configured

; Miscellaneous
M501 ; Load saved parameters from non-volatile memory

; config-override.g file generated in response to M500 at 2019-06-18 12:38
; This is a system-generated file - do not edit
; Heater model parameters
M307 H0 A90.0 C700.0 D10.0 S1.00 V0.0 B1
M307 H1 A340.0 C140.0 D5.5 S1.00 V0.0 B0
M307 H2 A340.0 C140.0 D5.5 S1.00 V0.0 B0
M307 H3 A340.0 C140.0 D5.5 S1.00 V0.0 B0
M307 H4 A340.0 C140.0 D5.5 S1.00 V0.0 B0
M307 H5 A340.0 C140.0 D5.5 S1.00 V0.0 B0
M307 H6 A340.0 C140.0 D5.5 S1.00 V0.0 B0

G10 L2 P1 X0.00 Y0.00 Z0.00
G10 L2 P2 X0.00 Y0.00 Z0.00
G10 L2 P3 X0.00 Y0.00 Z0.00
G10 L2 P4 X0.00 Y0.00 Z0.00
G10 L2 P5 X0.00 Y0.00 Z0.00
G10 L2 P6 X0.00 Y0.00 Z0.00
G10 L2 P7 X0.00 Y0.00 Z0.00
G10 L2 P8 X0.00 Y0.00 Z0.00
G10 L2 P9 X0.00 Y0.00 Z0.00

Ok , I've taken 3v from external source, that could be the reason, coz my Duet 3.3V rail conked off

Duetwifi 2

Due to this the main page of DWC act differently ("Processing " indication at the left corner changing every sec. to "off" and conmes back

This warning message is keep on coming every sec, what could be the issue?
otherwise all works fine

Firmware V2,03

Its happening exactly on the same points, I've checked duet connectors, cable swap done - need to check the motor connector...
but how that happens only in those points...

shared the video, after the issue, every layer in that portion not getting printed (extruder motor starts rumbling that point and again starts working normal after crossing the region..
Its happening for all the models...Initial layers are getting printed in-between all of a sudden the extrusion issue pops up..