If OWA and Outlook fail and the OOO still remains on, you can use MFCMAPI to turn turn off the OOO as well. MFCMAPI is a free tool hosted on CodePlex which is the Open Source Community from Microsoft.
1.Make sure Outlook is closed and then start MFCMapi.exe
2.In the main window choose;
Session-> Logon and Display Store Table
3.Select the Outlook mail profile to logon to when prompted.
If you do not recognize this dialog, simply press OK to load you default Outlook mail profile.
4.You’ll now see a list of your configured message stores in your mail profile.
Select your mailbox by looking at the Display Name column.
5.In the pane below, some properties will get loaded.
Look at the Property Name(s) column and select the entry called;
6.When you look at the Value column for this property, you’ll see it is now set to True.
Double click the entry to disable the check box in front of “Boolean”.
7.Press OK to close the dialog.
8.Log off your session via;