In Synchronous Database Mirroring (High-Safety Mode), only when the partners are connected and the database is already synchronized, manual failover is supported.

Automatic failover requires the database must be already synchronized....

install VMware workstation/player and create 3 notes on top of it..   then you can configure always and test as much you..

please follow the below link..

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/78d547cd-03b0-4ecb-96d8-c86fa95265cf/find-the-login-history-for-last-one-month-in-sql-server?forum=sqlsecurity

check the logs in setup/Bootstrap folder.. you can find current date once folder.. and then check which step it was struck..