Most of the emails are being tagged as spam by Outlook.

Step 1: Open Outlook and navigate to File > Options.

Step 2: Switch to Add-ins tab and click on Go button at the bottom.

Step 3: The list of available Add-ins will be displayed in the next window.

Step 4: Find and uncheck the checkbox respective to the antivirus add-in.

Step 5: Click OK and restart the Outlook client.