How to handle custom validation errors on saving to user model?

[Ohnoimded]

I'm having a validation check on username field. When validation error is raised, it throws Error 500. Is there a way to handle this? The "ACCOUNT_USERNAME_BLACKLIST" config is not enough as I'm creating the username from email and there is not username provided by the user while signing up.

[pennersr]

Can you paste the backtrace? Btw, you can also look into using the clean_username adapter method...