First restart your computer and all saved password you have tried with are gone.
Then you should set a password on the account you try to authenticate with. or else you have to enable the function/settings "Accounts: Limit local account use of blank passwords to console logon only". That can be made in 2 different ways.
1. Throw gpedit.msc -> Computer Configuration -> Windows Settings ->Security settings -> Local Policies -> Security options -> Accounts: Limit local account use of blank passwords to console logon only -> Disable (Default Enable).
2. Throw regedit. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\limitblankpassworduse: 0x00000000
The second way is meant to you if your using Home Premium and don't have access to gpedit.msc