Keep getting Error 3840 whenever i try to log into Sling Tv can anyone help

If you are still having this problem, make sure there is not a special character, especially "=", in your email address or password. An equal sign will exit the string that you're entering and Sling's software doesn't know how to deal with that yet. You should be able to sign in on a computer and change your password from there. I hope this helps -- It worked for me

I wanted to weigh in on this and leave an answer that worked for me, for those Googling the issue. It IS the presence of an "=" sign in your password that should be the root of the problem. I removed that from my password (along with an "!" for good measure) and it immediately cleared up the problem.

I was chatting with a Sling chat rep while I was doing this troubleshooting. He said they had never heard of this issue, but it's clear that it exists. To test it, I actually changed my password BACK to include the "=" and the problem reappeared. It's definitely a bug that their password creation process does not flag for you.

Hope this helps someone else Googling this issue.

Contact the app vendor. This isn't an Apple product.

Is the app you're using up to date?