I've been having the same error for over a week with Fubo. I posted about it 5 days ago.
Yeah it's weird that it only happens with channels, I even tried a browser that hadn't been on foxsports.com before and it worked fine with my provider's credentials, so go figure.
My credentials are fine and haven't changed in a year and a half now, if they were wrong I wouldn't be able to pull in much of anything on a rescan. For example definitely not ESPN and friends which work fine. All of the other Fox channels like FX etc. work it's just FS1 and FS2 that don't.
Will definitely need to email support since it is a channels specific problem.
So, the good is that FS1 is still in TVE and recording. The bad thing is I am seeing audio issues for the Fox signal: 2 seconds of audio and 2 seconds of silence repeating EXCEPT commercials, which play uninterrupted audio.
No issues with recording through ADBtuner.
Got same response from channels support, so I assume the issue is with TVE only.
FS1 & FS2 came back for me today. But my local FOX (WTTG) disappeared:
https://api3.fox.com/v2.0/liveplayer/5836e01f3f93d90001ab6627?geoLatitude=(mylocation)&geoLongitude=-(mylocation)&epgListingId=WTTG-program-WTTG-1739966400000: 403 Forbidden: "{"@context":"http://www.w3.org/ns/hydra/context.jsonld","@type":"Error","n…":"Invalid AccessToken Key Id","detail":"Key Id not found or supported"}\n"
I tried unchecking and re-checking "Local Networks via TV Everywhere" and updating to the latest pre-release... no joy.
FOX is hit or miss TVE-wise. It may pop up randomly one day or not. If you want FOX, then you're better off using a HDHR or a HDMI encoder
Sadly WTTG only ever comes in during the summer for me even with an outdoor antenna & pre-amp. I haven't been able to convince the wife to "invest" $200+ on an encoder yet 
The word, from a reliable source, is this little guy will do the encoder job on the cheap:
Combine it with a streaming stick you already own, or a $20 ONN stick, and you're in under $100.
2 Likes
I only spent 140 on mine so...yeah
I needed a second tuner so i got the usb hdmi encoder costed about 10 bucks and the onn stick was 20 bucks and the spare firetv stick I already had so that didn't cost anything. If you have any spare android tv devices in your house, you might save a bit more really
Can you share the link to the $10 encoder you mentioned? I looked up the MINIENC1 but the cheapest I could find it for was $80.
Just noticed that my DVR had updated to latest stable release yesterday, did a rescan this morning and got my FS channels back! Probably just a coincidence
https://a.co/d/inl2CMU
$10 video encoder that plugs into a $130 LinkPi encoder to handle 2 streaming devices
1 Like
The $10 device is a capture "card" not an encoder -- you still need an encoder.
Your choices are the MINIENC1 for ~$80, which is an encoder, but can only handle one input. Or, you can get the ENCV2 for ~$130, which can support a capture card for a second input.
And now it's gone again for me this morning, both channels are saying 503 service unavailable. Was working fine yesterday.
Good thing I have a E+TV as a backup to get the stuff that I want on Fox.
Probably not helpful, but working fine here, YouTubeTV.
Working here with Xfinity TVE
Working with Sling TVE.