This Kb describes how to fix the Last Config field in MIST with reason Unknown - --

Last Config field in MIST with reason Unknown - --

The last config status and commit time could be empty under various circumstance.

1. Missing Redis cache data - last_config_timestamp or min_config_timestamp not in Redis
2. Device not reporting complete oc-stats - Missing intent_version, running_version, or applied_at
3. Device disconnected - Status != 'connected', so function never called
4. Stale stats - Device hasn't reported in > 3 minutes

To fix the issue you can re-sync the configuration from MIST.

>> Select the site

>> Navigate to WAN Edges 

>> Click on the name of the device

>> Click on Utilities (top right corner)

>> Select 'Sync Configuration' 

Note: Please reach out to JTAC if the issue has been reported, as a resync might restore functionality. However, to determine what triggered the issue before performing the resync, we will need to collect the relevant logs.