This is a bug about the website https://identity.kde.org/index.php?r=registration/index I have created a user account years ago. Now I come back, and do not remember the username or the password. Only the email. It should be possible to reset password only with the email. Thanks
This is a known issue i'm afraid, which we plan to fix when we replace the whole system. This is being tracked at https://phabricator.kde.org/T8449 In the meantime, i've sent your username to you.