diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4034281bcd400bde1d17496637f5318f336fc8b1..b9552f9bdbcd7c1cabb6186a6a261ca6ea3988cc 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -56,13 +56,13 @@ Check links for md-files:
 Release preview branch:
     stage: release
     script:
-        - docker run --rm -v /var/www/html/preview:/mnt "${DOCKER_IMAGE}" mkdocs build --site-dir /mnt
+        - docker run --rm -v /var/www/html/preview:/mnt "${DOCKER_IMAGE}" mkdocs build --strict --site-dir /mnt
     only: [ preview ]
 
 Release:
     stage: release
     script:
-        - docker run --rm -v /var/www/html/hpc-wiki:/mnt "${DOCKER_IMAGE}" mkdocs build --site-dir /mnt
+        - docker run --rm -v /var/www/html/hpc-wiki:/mnt "${DOCKER_IMAGE}" mkdocs build --strict --site-dir /mnt
     only: [ main ]
 
 Cleanup docker: