diff --git a/.github/workflows/single-postgres.yml b/.github/workflows/single-postgres.yml
index b74e9629..bd603417 100644
--- a/.github/workflows/single-postgres.yml
+++ b/.github/workflows/single-postgres.yml
@@ -42,6 +42,9 @@ jobs:
       - uses: ankane/setup-postgres@v1
         with:
           postgres-version: ${{ inputs.postgresql }}
+      - name: Check pg_hba
+        if: ${{ failure() }}
+        run: ls -l /etc/postgresql/
       - name: Check installed locales
         run: |
           locale -a
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c6dee75d..8ce59dc5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -22,18 +22,21 @@ jobs:
     uses: ./.github/workflows/single-postgres.yml
     with:
       postgresql: 15
+      os: "ubuntu-22.04"
       python-versions: '["3.11", "3.12", "3.13"]'
   postgresql_14:
     needs: [postgresql_15]
     uses: ./.github/workflows/single-postgres.yml
     with:
       postgresql: 14
+      os: "ubuntu-22.04"
       python-versions: '["3.13"]'
   postgresql_13:
     needs: [postgresql_14]
     uses: ./.github/workflows/single-postgres.yml
     with:
       postgresql: 13
+#      os: "ubuntu-20.04"
       python-versions: '["3.13"]'
   macos_postgres_17:
     needs: [postgresql_17]
diff --git a/newsfragments/+a84dfbc9.misc.rst b/newsfragments/+a84dfbc9.misc.rst
new file mode 100644
index 00000000..c904a412
--- /dev/null
+++ b/newsfragments/+a84dfbc9.misc.rst
@@ -0,0 +1 @@
+Downgrade OS for certain postgres versions on CI.