Enabling the option is not enough, you have to convert all your user login from username to email. This is how I did it and it worked;
- Backup the database
- Look for all trackers with a username selector field
- Once field identified convert then username for the user email directly in mysql
Here for a fieldId 1 in a tracker
update tiki_tracker_item_fields i inner join users_users u on i.value=u.login set i.value=u.email where i.fieldId=1;
- Repeated this for all trackers username selector fields
- Copy the email over the login in the users_users table
UPDATE users_users SET login=email;
You may need to clean duplicates... search replace or manually
- Clean the Notifications list if used.
On the notifications the username is hard-recorded, you need to tracker the users for whom it is needed to replace the username with the email.
- Reinstate the admin account (last but not least), go back to users_users and normally your very first user is the admin, replace the login (email) with "admin.
That's how I did and it worked just fine.