Skype for Business has the ability to keep you signed in, but not for an infinite amount of time.
Without “Keep Me Signed In” checked you will stay signed in for a maximum of 12 hours.
With "Keep Me Signed In” it can be up to 7 days.
However, there are numerous factors that may mean authentication is required earlier than this, it isn't just a random prompt for your credentials. Some include:
- IP Address changes
- alterations to IE temp internet files
- certain Windows / Office updates
- PC sleep states
Skype for Business aims to be protective of it's ability to stay logged in at all times. As there is the risk of high call charges if it is used without the correct authorization.
At times having to re-enter credentials can be slightly distracting from day-to-day work; however, security is of such a high importance for us and all of our customers that the few seconds required to login is a worthy sacrifice to ensure that your call usage is safe and secure.
The exact methods used to determine whether or not the Skype for Business web authorization token is valid or not is not publicly available. The items listed in this article will cover the majority of the reasons why a re-authorization may be prompted for.