Can't Kill Ancient (Valheim)

I can’t kill the ancient, his health is completely restored

This was not the case.
If you play alone, don't create any servers - just single player and that's it.
If on a pirate, change the repack - I recommend it from the pioneer.

Accidentally discovered an easy way to defeat the ancient. You build stairs to the tops of the columns, and then on them the floor and small walls. It looks like a tower. Then you shoot with a bow