Which Mesh system is it - make/model?
In any case its always best to set it up with the Hub in modem mode following this procedure.
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Disconnect all cables from your new router (or Mesh first unit) and unplug it.
Put the VM Hub into modem mode (
https://www.virginmedia.com/help/virgin-media-hub-modem-mode ) and wait for the base light to turn magenta/purple (on a Hub3 - but not on a Hub4!). Once it’s in modem mode, the VM hub must then be powered off.
Then, set up your own router/Mesh with the WAN port set to be in DHCP & Nat mode - it will be in the network settings on the App - it may be pre-set that way anyway. Make sure it’s fully initialised (leave 5 min) and then put in the WAN ethernet cable to the VM hub (any port).
Now power up the VM hub and leave 5' to initialise you should get a connection. Then use the recommended App to connect the other Mesh units to the first one. This order only needs to be done the first time you connect the router to the VM hub.
Note that some TP-Link Deco’s systems need to be connected to the internet to set up the DHCP/Nat mode so that “may” need to be done first and then start this sequence again
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John
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I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.