diff --git a/.github/workflows/pr_to_gh_page_repo.yml b/.github/workflows/pr_to_gh_page_repo.yml
index 9a1b9ac2a..92de59370 100644
--- a/.github/workflows/pr_to_gh_page_repo.yml
+++ b/.github/workflows/pr_to_gh_page_repo.yml
@@ -29,6 +29,7 @@ jobs:
         with:
           key: ${{ secrets.SSH_PRIVATE_KEY }}
           name: id_rsa
+          known_hosts: unnecessary
 
       - name: Send pull-request
         run: |