Verizon LTE signal bouncing\lost on half of our MX67

[ZeeBoussaid]

Hello, I hope someone will assist in this, I know they are multiple topics regarding the LTE and almost all point out to the APN needs to be applied to all MX by Meraki, but I did open a case and they said the APN is correct (vzwinternet).  we implemented around 200 MX starting 2019, everything was working exactly how it suppose to be. these MXs are in a network closets and no one can get near them so i know the sims were working because i have a spread sheet with the LTE strength for every office. fast forward to couple months ago when i notices the offices with poor to OK signal are now showing no signal at all and some office with the LTE keeps bouncing, i literally can sit and watch it change from ready to no signal, even took a screen video clip and uploaded to Meraki. the reason we started this because we are planning on installing Verizon antennas connected to the MX to give us reliable signal in rural areas. at this moment we only seeing ~100 MX reporting their LTE status, so now Meraki is telling me we need to RMA these MXs also the keep insisting on a hard reboot to "collect logs" which i did and still didn't fix the issue. The hard reboot scenario is not feasible, these offices are busy and I cant keep shutting them down every time just to find out the issue is not fixed. steps i took:

1. soft reboot (via dashboard)
2. remove sim, unplug MX, install sim, power back MX ( i know these MXs dont like when a sim is installed while they are running)
3. another hard reboot.
4. still the sim modem will not pick up any signal at all

[ZeeBoussaid]

since no one seems to know the deal about the bouncing LTE on MX67, i'll share what Meraki did to fix the issue. the problem on the MX with bouncy LTE is the SIM context that the APN is pointing to was not applied to the correct SIM context. This issue was on 14.42+ and fixed on 14.46 + and when the firmware was upgraded from 14.42 to 14.53 several MX's had the incorrect context so that issue carrier over in the firmware upgrade. so Meraki pointed the APN vzwintenet to the correct SIM context and seems to fix the issue.

[ZeeBoussaid]

25 MXs need to be RMA, 23 was fixed by Meraki (re-apply the APN to match the SIM context -whatever that means-), 85 MX needs to be hard rebooted. this defeat the whole SD-WAN redundancy notion, and Meraki is not even sure if it's hardware or firmware issue. i hope this can helps.