I reboot the modem (randomly ssh or webclient), it recovers, works for a bit and fails.
The firmware is already the latest.
When I run the troubleshooter from ssh it is very slow but it does run. The gsm.log file reports the following information which is indicative of a failure of the modem to respond on the tty device.
[MODEM: "1-1" GSM INFORMATION]
connstate: Disconnected
netstate: GSMCTL error: reading message
N/A
imei: GSMCTL error: reading message
N/A
model: GSMCTL error: reading message
N/A
manuf: GSMCTL error: reading message
N/A
serial: GSMCTL error: reading message
N/A
revision: GSMCTL error: reading message
N/A
imsi: GSMCTL error: reading message
N/A
simstate: GSMCTL error: reading message
N/A
pinstate: GSMCTL error: reading message
N/A
signal: GSMCTL error: reading message
N/A
cellid: GSMCTL error: reading message
N/A
operator: GSMCTL error: reading message
N/A
opernum: GSMCTL error: reading message
N/A
conntype: GSMCTL error: reading message
N/A
temp: GSMCTL error: reading message
N/A
network: GSMCTL error: reading message
N/A
serving: GSMCTL error: reading message
N/A
neighbour: not supported
band: GSMCTL error: reading message
N/A
software: GSMCTL error: reading message
N/A
[MODEM: "1-1" GSMD log of gsmctl]
Sat Mar 19 19:03:54 2022 daemon.info gsmd[2730]: gsmd[dispatch_queue_work():914]: Modem 1-1 is not responding for over 500 seconds. Current request is cancelled.
Sat Mar 19 19:12:15 2022 daemon.info gsmd[2730]: gsmd[dispatch_queue_work():914]: Modem 1-1 is not responding for over 500 seconds. Current request is cancelled.
[MODEM: "1-1" GSMD AT commands]
ATI: GSMCTL error: reading message
N/A
AT+CGATT?: GSMCTL error: reading message
N/A
AT+CGDCONT?: GSMCTL error: reading message
N/A
AT+CGACT?: GSMCTL error: reading message
N/A
After a reboot the output looks good. i.e. the troubleshoot file reports as below and sending and recieving SMS works ... for a few message. Like ...
[MODEM: "1-1" GSM INFORMATION]
connstate: Disconnected
netstate: registered (home)
imei: 868159055296938
model: SLM750-V
manuf: MEIG
serial: 868159055296938
revision: 750VAU1DYB082500261
imsi: 530011116276194
simstate: inserted
pinstate: READY
signal: -61
cellid: 1327383
operator: Vodafone NZ vodafone NZ
opernum: 53001
conntype: FDD LTE
temp: 330
network: +SGCELLINFOEX:LTE,FDD LTE,530,01,1327383,105,5185,23,45168,3,100,1800,19800,-61,-91,-9,204,20,4,255,-,-,1,-,0,-,0,0,0
serving: ^CELLINFO:LTE,FDD LTE,530,01,1327383,105,5185,23,45168,3,100,1800,19800,-61,-91,-9,204,20,4,255,-,-,1,-,0,-,0,0,0
neighbour: not supported
band: LTE 3
software: SLM750-V_4.0.11_EQ101