config Pleroma.Web.WebFinger doesn't work

https://docs.pleroma.social/backend/configuration/how_to_serve_another_domain_for_webfinger/

I host pleroma at like pleroma.example.org and want users identified by user@example.org.

I followed these instructions, changed Pleroma.Web.WebFinger to example.org and kept Pleroma.Web.Endpoint as pleroma.example.org. Then I find users still identified by user@pleroma.example.org and seems Pleroma.Web.WebFinger config didn't work.

Not sure if I have the right configuration.