Hi Kheise,
Based on my experience, the issue could be related to the damaged identity in Outlook for Mac 2011. To solve the issue, please try creating a new identity by following the steps below:
1. Quit all applications.
2. Hold down the Option key on the keyboard, and then click the Outlook icon in the dock. The Microsoft Database Utility will open.
3. Click the plus [+] sign to add a new identity, and then type a name for the new identity. For example, type New identity.
4. Set the newly create identity as the default. To do this, select the newly created identity, click the Action button, and then select Set as Default.
5. Quit the Microsoft Database Utility, and then restart Outlook and see whether the problem is resolved.
For more details, please refer to the step 5 in Rebuild the Outlook for Mac 2011 database to resolve problems
Thanks,
Bourne Zhang
