If you sign into Skype, but you're immediately signed out and see the message "You have been signed out," please follow instructions below.
If you see this message when you're signed out:
You could be trying to sign into a retired version of Skype. If this is the case, simply click Download the latest version now, then follow the steps to upgrade to the latest version for free. You can also follow the detailed, step-by-step instructions here to resolve the issue and continue using Skype.
If you still can't access your account, follow the steps here.