BG95-M2 AT+HTTPOST CME 714 DNS lookup error

IoT Modules LPWA Module
1

Firmware version BG95M2LAR02A04.

SIM card: 1nce

Experienced CME 714 DNS look up error.

AT+COPS=? show the AT&T T-Mobile and Verizon network available .

Try to set up AT+COPS=1,2,“310410”,8 (AT&T). Everything works for https API call.

Try to set up AT+COPS=1,2,“310260”,8 (T-Mobil). Start to see 714 DNS Error.

Since then even if you go back to AT&T network, you always get 714 error on AT+HTTPOST=176,30,60.

Try to change the DNS server setting, AT+QIDNSCFG error. Looks like BG95-M2 not support this command.

In BG95 AT+HTTPOST (https) implementation, how the C code to resolve the DNS in UDP call? Does it has timeout setting for this DNS call? Is network slowness could cause this timeout? How many time it try to resolve the DNS? (This could related to too many DNS call happens and Google DNS could reject the request and we believe it may caused DNS error). Thank you very much if you could light up the puzzles. Is it possible that we could change the DNS servers for HTTPOST request? Thanks.

2

The BG95-M2 is support AT+QIDNSCFG and you can Refer to this picture.
image

3

We don’t have either of these cases. With same AT commands running, the only difference is we are using AT&T (works) and T-Mobile (break everything). We have to wait couple hours and run it again roaming to AT&T and it will work. 1nce SIM card network engineer told us no traffic is logged in their end.

4

We found the network trace showing that BG95 had so many DNS query against Google DNS servers. Each query came back with right response of API IP address. Can someone could tell based upon the BG95 firmware on AT+HTTPOST code that how firmware request repeated DNS requests?