Checklist: can’t receive messages from device

Figuring out at what step in the connectivity chain the problem is and how to fix it.

As flespi can get into work as soon as the device connects to your channel’s host:port you need to make sure that device can reach it. 

path to flespi channel

As soon as a new connection appears in the flespi channel, you will see the appropriate log in the channel Toolbox:

flespi channel connection log

If you don’t see any logs in your channel, your device cannot reach your flespi channel host:port. Therefore, neither flespi nor the flespi team can help you. Following is the checklist to verify all the links in the chain before data gets from the tracking device to flespi:


  1. The device has a power supply

  2. SIM-card is installed

  3. All required sensors and antennas are connected

Internal logic

  1. Depends on the device: some devices must have a GPS signal to start sending data, be unlocked using a certain software tool, somehow activated, etc. Check the documentation carefully


  1. SIM-card has a positive balance, the plan allows using the Internet, SIM-card is not locked by PIN-code

  2. APN settings are set (maybe set up from the flespi device configurator via SMS)

GSM carrier

  1. Carrier provider does not block access to flespi IP address (see subsections about SIM card below)

You might think that the problems are on the flespi side, but we can assure you that flespi is up and running.

How to check that SIM-card can connect to flespi

To check that the problem is on the device layer and connectivity issue is caused by the tracking device itself but not by SIM-card problems or GSM carrier settings you may do the following:

  1. Insert SIM card in the smartphone

  2. Install any application that can open a connection to the desired host:port. E.g. telnet (iOS, Android)

  3. Test if the smartphone can reach your host:port by checking the appropriate log in Toolbox

How to check that SIM-card can receive SMS from the flespi modem

In the same way, you can test if the flespi modem can send SMS to your carrier (some carriers may block SMS from outside the country). Send any setting via SMS from the device configurator tab while the SIM card is inside the phone. If you don’t receive any message, it might be blocked by your carrier. Having your own SMPP modem that can work in your country often helps.

See also
Manually posting messages into a flespi device.
An easy way to generate messages for a flespi device to test and debug plugins, streams, calculators, etc.