Here are three things to check before attempting to integrate with Alexa.
1. The wi-fi bridge has the latest firmware. If you go to Settings, there is no orange dot next to the wi-fi bridge name (or the lock). An orange dot means there is a firmware update recommended.
2. The connections are stable
If you go to Settings > WiFi Bridge Settings > [Property Name], the diagram must show all GREEN lines. A red line means there is no connection.
3. The wi-fi bridge is showing a SOLID GREEN light again after the firmware update. Firmware update may take a few minutes. Please note that the wi-fi bridge blinks and switches off during firmware update. It will go back to SOLID GREEN once the update is done and it has re-established connection with the lock and the wi-fi network.