Can we check… are your issues only evident on wifi connections or do you see them at the same times on devices connected on ethernet cables?
If you don't know, can you check that to help diagnose whether it is just a wifi issue - or it could be network connection/Hub related? Different solutions apply in those two options.
What Hub model is it? What are the various Hub lights showing/doing when this happens if a Hub3 is the base light a steady white(ish) or flashing green?
Also just do a check for any known issues - try in 2 places
1) Try the “check service,”Area status webpage" (link at top right of this forum)
2) Then also try the “free & automated” Service Status number - 0800 561 0061 - which usually gives the most up to date info. and tells you of more local issues down to street cab/ postcode level.
I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired, 1 WiFi, 1 on PA) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's. On 250Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.