@Theeyeinthesky you are right, it doesn't work between two omada routers, i did a test here with an ER605. it ended up that i had to do a full reset on the router, i have the same router against...

@Ronczkos since you are afraid to try, I did :-) I have connected a USB to Rj45 adapter on an ER706W, to my great surprise it worked right away.

@Theeyeinthesky I think I misunderstood your question., you can use wireguard to solve your problem. here is a guide, on remote site set allowed ip to 0.0.0.0/0 then all trafill will go out to main...

@Theeyeinthesky use sd-wan. gobal settings, sd-wan or folow this guide https://community.tp-link.com/en/business/stories/detail/502060

@Mellx1 Yes, this is for rj45 copper cable. https://www.omadanetworks.com/en/business-networking/omada-accessory-module-cable/sm331t/

@Mellx1 these should work, you must have A and B modules for them to work together, you cannot have two of the same on the same fiber cable....