Sign in error.

I've been experiencing no issues like this in the past but recently I've had trouble with a problem regarding me getting the error code Cauldron. Now normally this would be an easy solution but after following every tutorial from the Mojang website and from YouTube I have found no solution to this problem. To summarize I can't sign into my account because of this error code. My username is OWNING U or OWNING_U for reference.

 

Thanks!