Resource not found error, cannot edit setting. Problem finding setting: newsletter_show_header

I’m running a self-hosted Ghost instance. I recently updated to 4.15.0, but now I get the following error in the Ghost Admin UI whenever I try to create pages or do anything aside from creating new posts.

Resource not found error, cannot edit setting. Problem finding setting: newsletter_show_header

Is newsletter_show_header a config.json setting? I tried running ghost migrate to see if maybe it was a DB migration issue, but Ghost CLI says there’s nothing to migrate.

EDIT: Also, I should add that I don’t use Email newsletters at all on this site.

Managed to solve this with a restart on Ghost and Nginx.