You've been signed out, We need your account info to sign you back in.
I have a sign-in issue when use skype for business from mobile devices to connect to Lync server 2013, users authentication progresses has an error: You've been signed out, We need your account info to sign you back in.
Amir Bijani commented
we solved our problem by changing the web service policy under the security tab on the section integrated windows authentication to "negotiate". this setting takes 2 months of my time.