Enable 'Allow accounts with same email'

If enabled, more than one user account can share the same email address. This may result in security or privacy issues, for example with the password change confirmation email. 

Step 1. Login as an administrator and select Administration.

Step 2. Select Site Administration

Step 3. Select Plugins tab

Step 4. Scroll down to find Authentication category

Step 5. Select Manage authentication

Step 6. Scroll down to find Allow accounts with same email

This feature is disabled by default, indicated by an un-ticked checkbox. Please note, by enabling this feature it may result in security or privacy issues, for example with the password change confirmation email. 

Step 7. To enable allowing accounts with same email, select the checkbox. A tick will appear, indicating that this has been enabled.

Step 8. Scroll to the bottom of the page and select Save Changes.

You can now create accounts that use the same email address.