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.