Display Validation Errors?

So I’m trying to update a user record, however, the debugger says

"Model not updated due to validation error."

I have no idea what the error is and don’t know how to check it either.

Could someone please shed some light on how to display validation errors?

Thanks.

http://www.yiiframework.com/doc-2.0/yii-db-baseactiverecord.html#$errors-detail