diff --git a/.azure-pipelines/templates/jobs/standard-tests-jobs.yml b/.azure-pipelines/templates/jobs/standard-tests-jobs.yml
index 3ff00b21a..fec11c6c5 100644
--- a/.azure-pipelines/templates/jobs/standard-tests-jobs.yml
+++ b/.azure-pipelines/templates/jobs/standard-tests-jobs.yml
@@ -73,6 +73,6 @@ jobs:
       - template: ../steps/tox-steps.yml
   - job: test_sphinx_builds
     pool:
-      vmImage: ubuntu-latest
+      vmImage: ubuntu-20.04
     steps:
       - template: ../steps/sphinx-steps.yml
diff --git a/.azure-pipelines/templates/stages/notify-failure-stage.yml b/.azure-pipelines/templates/stages/notify-failure-stage.yml
index 1542f5ebc..c47342690 100644
--- a/.azure-pipelines/templates/stages/notify-failure-stage.yml
+++ b/.azure-pipelines/templates/stages/notify-failure-stage.yml
@@ -5,7 +5,7 @@ stages:
         variables:
           - group: certbot-common
         pool:
-          vmImage: ubuntu-latest
+          vmImage: ubuntu-20.04
         steps:
           - bash: |
               set -e