After installing Polylang, you’ll see Header and Footer are missing. Here’re steps to recover them.
- Visit Dashboard > Languages > Settings > Custom post types and Taxonomies and check for DINE Blocks.

- Go to Dashboard > DINE Blocks > edit your Header block. Do nothing, just hit Update.

- Apply the same for other blocks: Footer, Transparent Header, Off-canvas.. all in your DINE Blocks list.
