Those not working error messages are often related to poor wifi connectivity and asking you to check ethernet cable connections to the tv box - If I were you I would first get my wifi sorted properly. I did that 20 odd years ago by buying my own better quality wireless router and have never had any VM wifi issues.
VM do recognise the modern wifi issues that customers experience (for several reasons) and so now offer a wifi guarantee to sort them - see this old post of mine...
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Do you know if its a wifi only issue (are ethernet connected devices ok?), if it is - then On a Hub3/4/5, you could first try separating the SSID's of the 2.4 and 5 GHz wifi bands by renaming them in the settings At the same time switch off "channel optimisation/Smart wifi” and “ apply and save the settings. All wifi devices will now need reconnecting to the best SSID at each location. Also use a wifi scanning App or Apple Airport Utility) to find the best wifi channels to use (just select and use channels 1,6,11 on 2.4GHz) - this often helps Hub users get better wifi performance - so its worth trying - but its still no substitute for getting better kit 🙂
To address the wifi issues, VM now supply “wifi Pods” (no longer doing cheap and cheerless and poor value “boosters”). However, their Pods are only free to customers on the 1GB, Volt (or old Ultimate Oomph) packages - is that you? If so they are worth trying - they should work for you. VM Wifi is now “guaranteed” to 30 Mbps/room it’s now called… Wifi Max
See if anything in here helps….
https://www.virginmedia.com/wifi-max
You call 0800 064 3850 to order the first one after scanning for blackspots using the connect App.- or just wait here for a VM person to respond in a day or two and they will sort the first one for you. If you do call dont get fobbed off by the offshore CS agents' saying you aren’t eligible - if you are - it is clearly stated on the webpage.
If not free to you… you will be charged £8/month for up to 3 pods (note - BT charge £10/mo for their whole home wifi solution). It’s a simple solution and should work for you. However, you would soon pay off that cost by buying your own wireless solution that will be yours to own and use forever (as I did in 2002!), although the VM Pods should be a simpler option.
If you do want to invest in better equipment, you would need to get either a… (1) Mesh System, (2) Wireless router, (3) Wireless access point(s), (4) a pair of good quality Wifi Powerline Adaptors, or a combination of (2&3).
£40-100 (that’s ~4->12 months of Max Pod rental) should sort it for most customers with an average sized property and usage. Spend more for more powerful equipment and additional advanced“features” - if required.