What Hub model is it?
And are the 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 to help diagnose whether it is just a wifi issue or it could be network connection/Hub related?
What Hub model is it? What are the various Hub lights showing/doing when this happens?
In any case can you do a Pinhole reset as below
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Firstly, make sure the Hub's sticker/card with the two passwords on it is still there and legible If not – DON’T DO IT !
With the Hub switched "on", disconnect any ethernet connections (leave the co-ax connected) and then push in the “reset pin” with the end of a paperclip/thin nail/SIM tray “tool” or similar (bigger items like ball point pen ends may not press it in far enough) until you feel it at the “stop point” and hold it there firmly for a "timed" minimum of 60 seconds do NOT manually restart the Hub at any time. Leave it 10' or so to stabilise and then your passwords/passphrase for both the Hub settings and the Wifi networks will revert to the two printed on the Hub sticker on its base/side/card. Make sure you use the wifi one for devices connecting to the wifi and the settings/admin one to access the Hub
See if that sorts it.
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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 on WiFi) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's & TP-Link Archer C64 WAP. On Volt 350Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.