Launcher/website requesting me to enter a new username as if my account is new, have owned this account since 2012 and have played every day for the past 6 years without any issues

As the title notes, both the launcher/website are requesting me to enter a new username as if my account is new; however, I have owned this account since 2012 and have played every day for the past 6 years without any issues. The username in question is "Elxtra"

I have attached a screenshot below as well.

The following user posted a similar bug report but it was marked as resolved without having resolved it, one might want to review it as well <MCL-21741>