If you cannot add attachments to your outlook web email (OWA) , check these tips:
1. This issue occurs because the attachment exceeds the message size limit. The default maximum message size for an attachment is 10 megabytes (MB).
2. One of the most common ways of transmitting computer viruses is through file attachments. To help protect you and your recipients against computer viruses, Outlook blocks the sending and receiving of certain types of files (such as .exe and certain database files) as attachments.
https://support.microsoft.com/en-us/office/blocked-attachments-in-outlook-434752e1-02d3-4e90-9124-8b81e49a8519
Note: If you’re using a Microsoft Exchange account, your email server administrator can unblock certain file types. Contact your administrator for more assistance.
3. When you click the paperclip icon to add an attachment in Outlook Web App (OWA), your browser should launch a file window so you can choose a file to add. If nothing happens when you click the attachment icon, this could be because:
You are using Google Chrome version 37 or later
In version 37 of their Chrome web browser, Google introduced a change which effectively disabled OWA’s attachments button.
You can work around the problem by using OWA light (click on More login options and then the Use OWA Light option before logging in) which uses a different system for attachments which works on Chrome 37+ as well as browsers without the Silverlight plugin.
On Windows PCs, you can also try upgrading Silverlight (see below) as this sometimes re-enables the attachment button.
Alternatively, you could use OWA with an alternative web browser, such as Firefox.
There is a problem with a browser plugin (“Silverlight”)
Other web browsers use a plugin called Silverlight to handle attachments but if the plugin malfunctions for any reason, attachments will cease to work.
In this case, the quickest solution is usually to install or upgrade Silverlight. The browser plugin is available for free from the Microsoft website and can be upgraded without administrator permissions:
