I have a similar issue. Yet my wifi module LED stays on. https://forum.duet3d.com/topic/7803/web-interface-shutting-down-during-printing

Is there a way to log info from web control into file? I need the info that has been lost douring the WC shutdown. (print time etc.)

08:17:32.178 : Ran out of output buffers at ../src/Networking/HttpResponder.cpp(950)
again

@dc42 yes, only M999 helped

SENDING:M552 S0
WiFi module is idle

SENDING:M552 S1
WiFi module is connected to access point TRILAB24G, IP address 192.168.1.223

SENDING:M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 2.01(RTOS) running on Duet WiFi 1.02 or later
Board ID: 08DDM-9FAM2-LW4S8-6JTDJ-3S06Q-TJZ7W
Used output buffers: 14 of 20 (20 max)
=== RTOS ===
Static ram: 28476
Dynamic ram: 97124 of which 16 recycled
Exception stack ram used: 436
Never used ram: 5020
Tasks: NETWORK(ready,328) HEAT(blocked,1240) MAIN(running,544)
Owned mutexes:
=== Platform ===
Last reset 09:38:09 ago, cause: software
Last software reset at 2018-11-29 22:56, reason: User, spinning module GCodes, available RAM 5036 bytes (slot 3)
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0041f000 BFAR 0xe000ed38 SP 0xffffffff Task 0x4e49414d
Error status: 4
[ERROR] Error status: 4

Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms, max retries 0
MCU temperature: min 31.4, current 31.7, max 32.0
Supply voltage: min 24.2, current 24.3, max 24.5, under voltage events: 0, over voltage events: 0
Driver 0: standstill, SG min/max not available
Driver 1: standstill, SG min/max not available
Driver 2: standstill, SG min/max not available
Driver 3: standstill, SG min/max not available
Driver 4: standstill, SG min/max not available
Date/time: 2018-11-30 08:34:51
Slowest loop: 0.89ms; fastest: 0.08ms
=== Move ===
Hiccups: 0, StepErrors: 0, LaErrors: 0, FreeDm: 240, MinFreeDm: 240, MaxWait: 0ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.079 -0.050 -0.032 -0.084 0.055
=== Heat ===
Bed heaters = 3 -1 -1 -1, chamberHeaters = 2 -1
Heater 1 is on, I-accum = 0.6
Heater 3 is on, I-accum = 0.1
=== GCodes ===
Segments left: 0
Stack records: 2 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s)

Still not working

SENDING:M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 2.01(RTOS) running on Duet WiFi 1.02 or later
Board ID: 08DDM-9FAM2-LW4S8-6JTDJ-3S06Q-TJZ7W
Used output buffers: 13 of 20 (20 max)
=== RTOS ===
Static ram: 28476
Dynamic ram: 97124 of which 16 recycled
Exception stack ram used: 436
Never used ram: 5020
Tasks: NETWORK(ready,328) HEAT(blocked,1240) MAIN(running,544)
Owned mutexes:
=== Platform ===
Last reset 09:34:43 ago, cause: software
Last software reset at 2018-11-29 22:56, reason: User, spinning module GCodes, available RAM 5036 bytes (slot 3)
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0041f000 BFAR 0xe000ed38 SP 0xffffffff Task 0x4e49414d
Error status: 4
[ERROR] Error status: 4

Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 15.8ms, max retries 0
MCU temperature: min 29.7, current 31.5, max 33.3
Supply voltage: min 1.9, current 24.3, max 24.5, under voltage events: 0, over voltage events: 0
Driver 0: standstill, SG min/max 0/194
Driver 1: standstill, SG min/max 0/185
Driver 2: standstill, SG min/max 0/195
Driver 3: standstill, SG min/max 0/1023
Driver 4: standstill, SG min/max not available
Date/time: 2018-11-30 08:31:24
Slowest loop: 92.72ms; fastest: 0.07ms
=== Move ===
Hiccups: 0, StepErrors: 0, LaErrors: 0, FreeDm: 240, MinFreeDm: 120, MaxWait: 1518588ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.079 -0.050 -0.032 -0.084 0.055
=== Heat ===
Bed heaters = 3 -1 -1 -1, chamberHeaters = 2 -1
Heater 1 is on, I-accum = 0.6
Heater 3 is on, I-accum = 0.1
=== GCodes ===
Segments left: 0
Stack records: 2 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is idle in state(s) 0
serial is ready with "M122" in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
Slowest loop: 89.10ms; fastest: 0.01ms

reloading did not help

I suspect babystep button. testing if it is related

update - issue not resolved
printer was not running since last time
today small 2h print, web interface is down
I canot connect with pronterface for M122
repetier host returns after connect atempt
16:04:11.737 : Ran out of output buffers at ../src/Networking/HttpResponder.cpp(950)