Can't change my username

[Nx_ev (Nex)]

“an unknown error occurred” when trying to change my username

Expected behavior

that my username is changed to Nx_ev

{% endif -%}
{% if step_2_field_2 and step_2_field_2 != “” -%}
Page URL: <{% raw %}>

A private message is associated with this bug report

[Nx_ev (Nex)]

Adding onto this

[Nx_ev (Nex)]

I have possessed this username before, just adding onto this before someone asks me.