Hi @DonLeonhard 

Thanks for reaching out to TP-Link Business Forums.

Based on your configuration, it appears that Link Backup (failover mode) is currently enabled. In this mode, the behavior you will be expected is that the primary WAN handles all traffic under normal conditions while the backup WAN remains offline and does not participate in load balancing unless the primary WAN is offine.

Though the backup WAN shows as Offline, it does not really mean it disconnects from the network. The system itself would still use multiple built-in public domain names to detect whether it is online. Alternatively, you can set the Echo Server to Custom and input 8.8.8.8 or another preferred IP or hostname to check if it remains active.

If you  would like to use both WANs simultaneously, you may need to disable Link Backup and switch to Load Balancing mode only instead.

Here are some articles for your reference:

How to Configure Link Backup on Omada Gateway via Omada Controller | Omada Network Support

The differences and similarities between Load Balancing and Link Backup | Omada Network Support