diff --git a/Dockerfile b/Dockerfile
index 5755c2b769928cd4047cc16c9a40a1769f0a04e2..4b11d882809ca6eb1d574e20306bb2cd279f5a42 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@ SHELL ["/bin/bash", "-c"]
 # Base #
 ########
 
-RUN pip install mkdocs>=1.1.2 mkdocs-material==8.5.11 mkdocs-htmlproofer-plugin==0.8.0 mkdocs-video==1.3.0
+RUN pip install mkdocs>=1.1.2 mkdocs-material==8.5.11 mkdocs-htmlproofer-plugin==1.2.1 mkdocs-video==1.3.0
 
 ##########
 # Linter #
diff --git a/doc.zih.tu-dresden.de/mkdocs.yml b/doc.zih.tu-dresden.de/mkdocs.yml
index fce102bcdcfabd7f24b240b96e578cc011345df9..de4fc725f543beb47f77c579e7158cc561e5f0ef 100644
--- a/doc.zih.tu-dresden.de/mkdocs.yml
+++ b/doc.zih.tu-dresden.de/mkdocs.yml
@@ -229,14 +229,20 @@ plugins:
       # Toggle via env. var. ENABLED_HTMLPROOFER=false
       enabled: !ENV [ENABLED_HTMLPROOFER, True]
       # Check URLs before serving. Build fails in case of bad URLs.
-      raise_error: True
+      # raise_error: !ENV [ENABLED_HTMLPROOFER_RE, False]
+      # raise_error_after_finish: True
       # Ignore errors
       #raise_error_excludes:
       #  504: ['https://www.mkdocs.org/']
+      #          405: ['https://jupyterhub.hpc.tu-dresden.de/']
+      ignore_urls:
+          - mailto:hpc-support@tu-dresden.de
+          - https://jupyterhub.hpc.tu-dresden.de/*
+      skip_downloads: True
       # Toggle validating external URLs
-      validate_external_urls: False
+      validate_external_urls: True
       # Validate the entire rendered template, slow!
-      validate_rendered_template: True
+      #validate_rendered_template: True
   - mkdocs-video:
       is_video: True
 
diff --git a/doc.zih.tu-dresden.de/util/check-links.sh b/doc.zih.tu-dresden.de/util/check-links.sh
index ab4fe5275cbfdae9200e85b2407fa98b37c850d2..05a1e69239f621b3ec99fb018c2d8b391a3d7e5c 100755
--- a/doc.zih.tu-dresden.de/util/check-links.sh
+++ b/doc.zih.tu-dresden.de/util/check-links.sh
@@ -5,5 +5,6 @@
 set -eo pipefail
 
 export ENABLED_HTMLPROOFER=true
+cd doc.zih.tu-dresden.de
 mkdocs build
 rm -rf public