diff --git a/.github/workflows/preview.yml b/.github/workflows/preview.yml
index b0fd68b1e..98306415c 100644
--- a/.github/workflows/preview.yml
+++ b/.github/workflows/preview.yml
@@ -54,6 +54,12 @@ jobs:
           BRANCH: "${{ env.GITHUB_BRANCH_NAME }}"
         run: make preview
 
+      - name: Get safe branch and export to env
+        env:
+          BRANCH: ${{ env.GITHUB_BRANCH_NAME }}
+        run: |
+          echo "SAFE_BRANCH=$(make safe_branch)" >> $GITHUB_ENV
+
       - name: Update PR Comment
         uses: actions/github-script@v7
         if: github.event_name == 'pull_request'
@@ -80,8 +86,8 @@ jobs:
               }
             });
 
-            const branch_name = process.env.GITHUB_BRANCH_NAME;
-            const url = "https://" + branch_name + "." + process.env.PREVIEW_HOSTNAME;
+            const safe_branch = process.env.SAFE_BRANCH;
+            const url = "https://" + safe_branch + "." + process.env.PREVIEW_HOSTNAME;
             const timestamp = new Date().toISOString();
             const header = "\n|Key|Value|\n|---|---|\n"
             const body = preview_identifier + header + "|url|" + url + "|\n|last update|" + timestamp + "|";
diff --git a/Makefile b/Makefile
index 37b1b7c9a..2d16e8e8f 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ export GIT_VERSION ?= $(shell git rev-parse --short HEAD)
 # Auto-detect and sanitize current git branch
 BRANCH ?= $(shell git rev-parse --abbrev-ref HEAD)
 # Replace "/" and other non-alphanumeric characters with "-"
-SAFE_BRANCH := $(shell echo "$(BRANCH)" | sed 's/[^A-Za-z0-9-]/-/g')
+SAFE_BRANCH := $(shell echo "$(BRANCH)" | tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9-]/-/g')
 FORCE_DEPLOY ?= false
 SITE_URL ?= "https://$(SAFE_BRANCH).ep-preview.click"