You should call it in as a fault and make sure you get a Tech visit to investigate - if its faulty they will replace the Hub.
You may want to try a reset of the Hub4 first.
Do a Hub “pinhole reset” - first make sure the 2 passwords on the Hub sticker are still there and legible first ! With the Hub still "switched on" throughout, press the reset pin in firmly with paper clip/SIM tray tool or similar "thin thing" and hold it firmly for at least 60 (a timed sixty) seconds, release the pin, leave for 5’ to stabilise - dont manually switch it off at any time. Passwords and SSID’s will reset to those on the sticker so log in and change them back to what they were/should be.
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.