Environment
Onomondo App: Network Logs
Device: Applicable to all devices with NB-IoT enabled
Issue
On the device
The device registers to NB-IoT network but fails to send data
In the app
There are "Attached..." and "Detached data connection" events in Network Logs
The "Detached..." data log shows 0 bytes for both Download and Upload
Solution
Check if ePCO is disabled. This AT Command is often proprietary and therefore changes between modules. It is best to consult the modem manufacturer's AT command manual for the correct command.
Example - the Nordic nRF91 series:
You can use AT%XEPCO? to check the modem's current ePCO configuration.
If the response is %XEPCO: 1, then you need to change it to AT%XEPCO=0 and try to connect to the network again.
Cause
Currently, Onomondo Packet Gateway does not support the ePCO protocol. When ePCO is enabled the IP configuration of the session is sent empty. This results in missing information provided in the configuration of the session (including IP address, DNS IPs, etc) and as a result the device looks online, but is unable to send any data.