brake line leaks around fitting on 1997 Buick LeSabre

I replaced brake line now it leaks around fitting around threads. I have tightened as far as i can and it doesnt help.

Asked by for the 1997 Buick LeSabre
If it threaded back together with no abnormal resistance when hand threaded then check for crack at line seat or incorrect seat at the end of line. There are differences.