On the assumption that it's a Hub 3 or 4 (?), then the white LED shows that the hub is operating normally and has a connection to the internet.
If you've tried the usual plug reset and reconnect routines as per the maker's guidance, then it's probably a hub compatibility issue. It is likely that if you've recently connected to VM, you'll need to go into the hub's advanced settings and turn off "intelligent wifi", any automatic optimisation or auto channel selection, and then rename the 2.4 and 5 GHz wifi signals with different names (by default they use the same name). In theory the hub and device should cope with a shared network name as there are established standards supposedly used, but for reasons we don't understand it is a common complaint that some dumb "smart home" devices won't work reliably with a VM hub when it has a single network name for both 2.4 and 5 GHz, even when they manage fine with other ISP hubs or third party mesh systems or routers.
