Hard to tell, since you didn’t share your code. But the error message tells you why.
But if you are trying to DEFINE previously defined constants (which is what those are, since they were defined in wp-config.php – look at that file in the indicated line number), then that would be the cause of your errors.
“Constants” are ‘constant’. Never-changing. Once defined, that’s it. Don’t try to change the value of a constant that has been DEFINEd.