# MC7455 Won't connect to Network **URL:** \ **Category:** MC/EM Series\ **Created:** [April 8, 2020, 11:41pm UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019 "2020-04-08T23:41:43Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![mindrcr](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mindrcr](https://forum.sierrawireless.com/u/mindrcr)\ **Post date:** [April 8, 2020, 11:41pm UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/1 "2020-04-08T23:41:43Z")
SIM works on Android phone, but not on MC7455. apn: [fast.metropcs.com](http://fast.metropcs.com) name = MetroPCS US LTE proxy = not set port = not set username = not set password = not set server = not set mmsc = [http://metropcs.mmsmvno.com/mms/wapenc](http://metropcs.mmsmvno.com/mms/wapenc) multimedia = not set MCC = 310 MNC = 260 authentication type = not set APN type = default,supl,mms APN protocol = IPv6 APN roaming protocol = IPv4 bearer = unspecified mobile virtual network operator type = GID mobile virtual network operator value = 6D Any ideas on how to get this connected? at!gstatus? !GSTATUS: Current Time: 281 Temperature: 35 Reset Counter: 1 Mode: ONLINE System mode: LTE PS state: Not attached LTE band: B2 LTE bw: 10 MHz LTE Rx chan: 1000 LTE Tx chan: 4294967295 LTE CA state: NOT ASSIGNED EMM state: Deregistered Limited Service RRC state: RRC Idle IMS reg state: No Srv PCC RxM RSSI: -68 RSRP (dBm): -101 PCC RxD RSSI: -70 RSRP (dBm): -101 Tx Power: – TAC: 0E00 (3584) RSRQ (dB): -13.8 Cell ID: 00378618 (3638808) SINR (dB): -1.2 OK at!usbcomp? Config Index: 1 Config Type: 1 (Generic) Interface bitmask: 0000010D (diag,nmea,modem,rmnet0) OK at+cmee=1 OK ati Manufacturer: Sierra Wireless, Incorporated Model: MC7455 Revision: SWI9X30C\_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30 MEID: 35907206649842 IMEI: 359072066498425 IMEI SV: 20 FSN: LQ950644740410 +GCAP: +CGSM OK at!priid? PRI Part Number: 9909124 Revision: 001.000 Customer: Generic-M2M Carrier PRI: 9999999\_9904609\_SWI9X30C\_02.33.03.00\_00\_GENERIC\_002.072\_000 OK at+cpin? +CPIN: READY OK at+cimi 310260353730494 OK at+cgdcont? +CGDCONT: 1,“IPV4V6”,“[fast.metropcs.com](http://fast.metropcs.com)”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0 OK at+cgpaddr=1 at!band? Index, Name 00, All bands OK at+cops? +COPS: 2 OK at+cops=? +cops: (0,“AT&T”,“AT&T”,“310410”,2),(0,“311 490”,“311 490”,“311490”,7),(0,“AT&T”,“AT&T”,“310410”,7),(0,“Verizon”,“Verizon”,“311480”,7),(0,“Sprint”,“Sprint”,“310120”,7),(0,“311 882”,“311 882”,“311882”,7),(0,“312 530”,“312 530”,“312530”,7),(0,“Metro by T-Mobile”,“Metro by”,“310260”,7),(0,“313 100”,“313 100”,“313100”,7),(0,“Metro by T-Mobile”,“Metro by”,“310260”,2),(0,1,2,3,4),(0,1,2) OK at+cops=1,2,“310260”,2 +CME ERROR: SIM failure ---
**Author:** ![Vianney](https://avatars.discourse-cdn.com/v4/letter/v/71e660/32.png) [@Vianney](https://forum.sierrawireless.com/u/Vianney)\ **Post date:** [April 9, 2020, 10:16am UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/2 "2020-04-09T10:16:17Z")
Hi @mindrcr, Maybe you can share some below: - Had the module worked perfectly with the SIM before? If yes, did you take any new settings? - The module respones +CME ERROR: SIM failure. That would also explain why you were unable to register with the network. Have you tried to reset the module? Please do an AT!RESET and try again - Did you remove the SIM for a too short period of time then inserting it again? If yes, it might cause the issue. Reset module will resolve the problem Please share any concerns you have. Help us tick **Solution** if your question is answered Thanks ---
**Author:** ![mlw](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/mlw/32/3706_2.png) [@mlw](https://forum.sierrawireless.com/u/mlw)\ **Post date:** [April 9, 2020, 10:37am UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/3 "2020-04-09T10:37:56Z")
@mindrcr, So you have the COPS mode set to 2 which is ‘deregister from the network’, I would suggest sending the below to the unit and letting it run to allow it to sort itself out. at+cops=0 at+creg=1 ;These unsolicited responses will give you a running indication of attach status at+cgreg=1 at+cereg=1 at!reset The SIM failure can quite often indicate that the unit has been rejected from the network in its attach attempt. Regards Matt ---
**Author:** ![mindrcr](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mindrcr](https://forum.sierrawireless.com/u/mindrcr)\ **Post date:** [April 9, 2020, 4:32pm UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/4 "2020-04-09T16:32:46Z")
The SIM works in an android phone. The SIM fits perfectly in the adapter with no edges causing issues. There are 3 drag marks across the SIM and adapter where the router is making contact. I have cleaned the SIM and tried inserting and restarting many times. Could it possibly be the SIM reader (hardware) issue? The only command that seems to fail is the at+cops commands. at+cgatt=1 ERROR at+ceer +CEER: EMM attach failed at+cops=0 +CME ERROR: SIM failure at+creg=1 OK at+cgreg=1 OK at+cereg=1 OK ---
**Author:** ![mindrcr](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mindrcr](https://forum.sierrawireless.com/u/mindrcr)\ **Post date:** [April 9, 2020, 10:07pm UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/5 "2020-04-09T22:07:15Z")
One further finding. The CNUM command is not bringing back the phone number. Will this cause an issue? AT+CNUM OK ---
**Author:** ![mindrcr](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mindrcr](https://forum.sierrawireless.com/u/mindrcr)\ **Post date:** [April 10, 2020, 10:12pm UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/6 "2020-04-10T22:12:35Z")
I tried a TMobile SIM and changed only the APN setting, no other changes. It connected right away. Must be the missing MSISDN number not returned by CNUM. Thanks for the help. ---
**Author:** ![dl5162](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dl5162/32/2169_2.png) [@dl5162](https://forum.sierrawireless.com/u/dl5162)\ **Post date:** [April 11, 2020, 8:07am UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/7 "2020-04-11T08:07:53Z")
I noticed that you were using IPV6 in your working Android example, but IPV4V6 with the MC7455. I believe this is more likely to cause issues if the APN only supports IPv6. ---
**Author:** ![swsdb](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@swsdb](https://forum.sierrawireless.com/u/swsdb)\ **Post date:** [October 22, 2021, 2:40am UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/8 "2021-10-22T02:40:17Z")
Was there ever a solution to this issue? I appear to also have an identical issue with a Google Fi (data or regular) SIM. I also have the data mode set to IPV6 only. ---
**Author:** ![swsdb](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@swsdb](https://forum.sierrawireless.com/u/swsdb)\ **Post date:** [October 22, 2021, 3:03am UTC](https://forum.sierrawireless.com/t/mc7455-wont-connect-to-network/20019/9 "2021-10-22T03:03:05Z")
Turns out the issue in my case was somehow the IMEI on the (legit) Sierra modem was reset/wiped in a botched firmware upgrade. Resetting the IMEI fixed it (though I assume we’re not allowed to say how to reset the IMEI on this forum).