"Twitch Broadcasting Unavailable: Authentication to Twitch failed..." when Twitch account was binded to Mojang account.

I was playing single-player "Minecraft 1.8-OptiFine_HD_U_A6" as according to the launcher, and that version has never had a problem before....

I was testing out the same single-player world using "Minecraft 1.8" as according to the launcher, and that version has never this problem before, either....
**I had no other mods installed for Minecraft other than Optifine on the modded 1.8 version previously used.

What I expected to happen was...:
When I tried to access the Broadcast Options, to move to that options screen freely, as usual;
When I tried to stream using the game's built-in stream start/stop keyboard shortcut, to begin streaming.
What actually happened was...:
A Twitch error message/screen appears, as shown below.

How it happened, etc:
When I press F6 to start streaming or click on "Broadcast Options" in any Menu screen:

My Mojang account page says it is linked, and my Twitch settings say it has been linked for 7 hours, which seems impossible, – although my Twitch was possibly hacked on 3/23/2015 ... – because I had just unlinked and then re-linked the two accounts less than 30 minutes earlier, after said issues were discovered.

I have tried closing out of and restarting the launcher but I haven't tried much else yet.

I searched for this issue and only found one that came anywhere close, although it was still obviously not the same issue as I was having.

I have not tried rebooting my desktop or logging out and back into the launcher, but I have shut down and powered it up again, just not in the same day (I have yet to see if that fixed it or not).
I have a theory as to why this problem could have occurred, but I won't know until sometime next week as to whether or not it could have had even the slightest effect on the situation.

Nevermind, it is fixed for Vanilla 1.8; Optifine 1.8 version seems to be fixed as well... maybe turning the desktop off and back on did it?