Your TiVo has a separate internet connection that doesn't use your home router.
2 things to check... if you follow Home > Help & Settings > Settings > Network, does the box report connected in the top-right?
Second, on the front left of your box are a series of green lights. The second from left has a heart symbol next to it and indicates your box's internet online status. It should be solidly on, but I'll hazard a guess you're is flashing?
If so, that's a box fault which is best reported to VM
Edited post now the OP has a V6 instead. Your V6 relies on your homehub for an internet connection, is this by Ethernet or WiFi? Please check the network screen in my second line above, and report what is showing.
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