Hi,
sometimes a transmitted payload will not be shown on ttn-server.
For example here, payload No 274 is not shown.
yes… that can happen, it’s radio after all 
Ok, but i mean it had be recognised , otherwise the next counter number should be 274 and not 275.
the server can’t know that … you could have taken the battery out of the device 
in general (see your other topic) YOU are responsible for managing and detecting in your application and taking action (or not)
for a temperature sensor in an office its maybe not so important to miss one, for an overheating machine it could be.
that last example… if the temp rises above a certain threshold the node only transmit ACK.
The counter is part of the transmission from the node. So gaps can occur and are not a problem.