I use the Netflix app regularly on my Roamio basic (OTA) but when I tried to access it a couple days ago I was presented with a V301 error. The message said to go to www.tivo.com/support/V301
for more information, but that link does not seem to be valid.
Everything else was working fine on the Roamio. I could use other network apps (Hulu, YouTube, etc), connection calls to TiVo central worked fine, accessing the unit via kttmg worked fine, all network diagnostics were good, the unit was still recording shows as expected, etc, etc. I also have two Minis on the network, and both of those were also working just fine, and the two Minis had no problem using the Netflix app.
I waited a couple days, but the issue did not clear on the Roamio basic. I ultimately resolved it by resetting the Roamio using the menu option (TiVo central -> Settings & Messages -> Help -> Restart or reset) Hopefully the problem won't recur.
I just figured I would post this in case it is helpful to someone else. I found a couple other forum postings that were similar to this issue, but none that were exactly the same.