Since last weekend (Jan. 26, 2019 or so), Netflix is unusable on my Roku 3 (4200). When I start watching something, it plays for a bit then stops to re-buffer (showing percentages) and then after a bit displays error "tvq-pm-100 (3.1.18)" with message "We're having trouble playing this title right now." I cannot figure out how to fix it.
Roku 3 (4200) showing OS is 9.0.0 build 4114-04
Connected via Ethernet cable directly to router.
I have tried all the troubleshooting I can think of. Restarted my home router (Verizon FIOS), restart Roku, uninstall Netflix app and reinstall app. At this point I have done a full factory reset of the Roku twice and started from scratch. No difference. I see no problems logged in my router's firewall log.
Streaming Netflix on my computer has no problem. Installed the Netflix app on my Playstation 4 (on the same network) and watched all night with no problem. Other apps on the Roku like Amazon Prime work with no issues. Seems like the issue is only the Netflix app on the Roku 3.
Everything has been working perfectly until a week ago (about January 26, 2019). Does that match the date of the push out of Roku OS 9? I was not monitoring what OS I was running and when updates happened so I have no idea if the OS updated right before this problem started. That's the only theory I have as to why this suddenly started happening.
Everything you've done seems in order. Well, actually a remove/reinstall should be remove, reboot, reinstall, in order to clear out any corrupt data remaining within the app. But, a factory reset should have accomplished the same thing, so we'll bypass that point. Just mentioning it if future troubleshooting is ever necessary.
OS 9 for Roku 3 came out last year. That is, it began rolling out last year, and should have completed by the end of December. Roku TVs are still getting the rollout, but your Roku box, of which I have the same, should have received the update from 8.1 to 9 late last year.
There was a build push, to build 4114, in mid-January, but you should have had that update prior to 26 Jan. I received mine on 21 Jan, so it is possible you didn't get build 4114 until 26 Jan.
However, Netflix has been working on my Roku 2 (model 4210), which is identical to model 4200. The 4210 and 4200 differ only in what was included in the cardboard box. 4210 had an IR remote, while 4200 had the WiFi Direct remote. The physical Roku devices have the very same components. When I say they're the same, I don't mean they're close. I mean they are the same. The plastic cover has a "2" on it, but inside the cover, again, the same. I do have a Roku 3 (4200) at another location, but it's a few hours away, so I can't check it to confirm it's also without issue.
One thing to check is your DNS settings on your home network. Record them, if you make a change while troubleshooting, so you can put them back.
If you're using Verizon's DNS settings (possible 184.108.40.206 and 220.127.116.11) you might want to change to Google DNS (18.104.22.168 and 22.214.171.124), CloudFlare (126.96.36.199 and 188.8.131.52) or some other. If that resolves it, you may find you want to keep those settings. Just hold on to the original information.
Apart from that, I got nuthin'