When hacking away at a new IoT Application you sometimes wonder why some data from some devices does not make it into SAP IoT Application Enablement. Of course there can be many obvious reasons like e.g. the device has no power, connectivity is down or intermittent, Internet not reachable from local network or proxy server is down. But if you suspect the reason is after the data reaches device management (aka IoT Service for the Cloud Foundry environment) then one place to look for lost data is the Error Messages api for your tenant. It’s described here: https://help.sap.com/viewer/350cb3262cb8496b9f5e9e8b039b52db/latest/en-US/7928e0354544424f834cea4c896e763c.html
The error messages in here address many different sources of problems and it’s a good idea in production to other then monitoring your other application components to also monitor this one. It could be for example that for a specific sensor the mapping has been deleted or that the meta-data of sensor vs thing has gone out of sync.
The good news for debugging a current situation is that with the latest release the scopes required to access this api are part of the typical thing-super-user role. So you can go ahead in your favorite browser and enter the following (replacing the tenant name iotae-weather-station with your tenant) to get the errors for a specific day:
This error log sticks around for 1 week and when you pick it up in time you can use the raw message in it to try to re-ingest the data with the original timestamp. Of course you have to first resolve the issue that made the ingestion fail and you should do this ahead of the end of the warm store retention timeframe (typically 3 months).