@DWie 

Thanks for reaching out to us. 

Currently, it is necessary to identify which deco stop broadcasting 2.4G network. 

Please power off two satellite deco and check if you can receive 2.4G network from the main.  If you can, then please power on satellite deco one by one to identify which satellite deco has issue. 

After you make sure which deco has the problem, please try reset and reconfiguration. If it is the main deco has issue, you need to reset all deco units and reconfigure. 

How can I reset or reboot my Deco Whole-Home Wi-Fi System?

If the issue can't be solved, please provide me the S/N of that problematic deco and the invoice of your deco as well. Thanks~