We have a Deco X55 Mesh system installed in our home in Panama.  We purchased an ER605 Dual WAN switch to connect the Tigo Fiber Optics and Starlink using the failover.  Tigo will be the primar and Starlink is the backup.  I have watched numerous videos on the setup and still cannot seem to get the setup correct for the ER605.  It will run perfectly for quite a few hours and then the Primary (Tigo) will fail and it will not swtich to the backup automatically.  If I restart the Tigo modem and connect to the Deco X55, bypassing the ER605, then Tigo works perfectly.  If I disconnect Tigo from the ER605 and only have Starlink connected to the WAN and then to the Deco X55, Starlink works perfectly.  

I think there must be a conflict somewhere but have not been able to find it.  I have changed the LAN IP address and associated ranges on the ER605 to 10.10.10.1.  This does seem to help the problem.  On Load Balancing, only the first bax is checked not the bottom two boxes related to Load Balancing.  

Please let me know if you have any suggestions.  Thanks