@fips, it is very likely your ISP used CG-NAT, shared by one community user:https://community.tp-link.com/en/home/stories/detail/1766

@Peterdu HI, It has something to do with this WAN/LAN auto-sensing and they have explained here:WAN/LAN auto-sensing

@Molaker Hi, later you could try the suggestion here and It should be the correct steps for you in the very beginning. https://community.tp-link.com/en/home/forum/topic/562204?replyId=1105698 As for...

@87rofg743uhi3f Hi， there are some beta firmware for this issue: https://www.tp-link.com/us/support/faq/3329/

@EricTheGrey Hi, it seems like you have a double NTA issue: Fibre internet router----<cable>----main w3600---<cable>----satellite W3600 ) ) ) ---WiFi---( ( (HP printer. \----<cable>---Office Desktop...

@ABMPC They are starting a beta test for Deco X55 1.1.0 now which allows the manual signal source selection per user: Deco X55 1.1.0