Not able to view attachments in the Outlook webmail itself.

Step 1: Sign into Office 365 admin portal via https://portal.office.com

Step 2: Click on Admin from the left pane and navigate to Exchange admin center.

Step 3: Switch to Permissions tab and click on Outlook Web App policies.

Step 4: Double-click on the Default policy.

Step 5: Switch to File Access tab and check the Direct file access checkbox.

Step 6: Click Save.