Hi hi! Thank you so much for reaching out, when someone changes their username on Deviantart, their DD account doesn't automatically update. In order to match your new Deviantart username to your DD account, please reply to this forum thread with your new username and the mod managing it will update it for you asap! https://darling-dainties.com/forums/622666a3360fa66986339817/threads/62266e75360fa66986339820 
You can also reach out on discord in the Website-Masterlist channel!

Thank you so much, hope this helped!