Some users, when attempting to respond to an approval request reminder via email, are unable to do so because a blank browser tab opens instead of a new email message. The reason for this is that the user more than likely has their default email application on their computer set to a web browser instead of Microsoft Outlook. Use the below instructions to adjust your settings so that Outlook opens a new email message when sending an approval response via email.
Windows Solution
Click the magnifying glass icon on your taskbar to search for programs.
Search for "Default Apps" in the search bar that appears.
Click on the result labeled Default apps, a part of the System settings application.
Under the Email section, click on the current default application.
In the list of options that appears, click on Outlook to set it to your default email application.