nrf9160 at_write() Failed to send AT command (err:22)

[nmlkpoiu]

Hi 
  We use INCE sim card in both Denmark and Sweden on our custom product. My main thread basically doing this:

lte_lc_offline();

lte_lc_init();

lte_lc_connect_async(lte_handler);

send socket to server;

go to sleep for x minutes;

and loop

This logic can work fine for 2 or 3 days without any problems; Then suddenly, the at_write() function starts to print "Failed to send AT command (err:22)" out and same thing happen to all the following ademptions of giving AT commands. And the Sim card can never registered again. Only resetting can make everything work normal again. But after another 2 or 3 days, this at_write() failure will happen again. Can you help?

 

nrf sdk version: 1.3.0; modem version: mfw_nrf9160_1.2.1; Device: happens on both 9160DK board and our custom board;

[nmlkpoiu]

I didn't use PSM. 

[nmlkpoiu]

trace-2021-02-02T21-38-21.889Z.bin2021-02-01T22_11_12.678Z-log.txt
 I reproduced this "Failed to send AT command (err:22)" error again after everything run OK for about 1 day on 9160DK board. Here is the log and trace file.
Seems like repeating this "connect" and then "offline" action for many times/hours will eventually trigger this "Failed to send AT command (err:22)" error.

[Heidi-Irene Harvey Sollie]

Hi!

I'm sorry about the slow response time. I just wanted to let you know I'm looking into your case now. 

Best regards,

Heidi

[Heidi-Irene Harvey Sollie]

Hi

We were not able to successfully parse the trace file you attached. There were fewer errors with the modem 1.2.2 database though, so I'm wondering if you're actually using MFW v1.2.2?

Are you able to take a new trace?

Best regards,

Heidi

[nmlkpoiu]

Hi Thank u for replying. But as I mentioned previously, I use mfw_nrf9160_1.2.1 not 1.2.2.