diff --git a/compose.yml b/compose.yml
index 8a533ec..23db337 100644
--- a/compose.yml
+++ b/compose.yml
@@ -7,8 +7,8 @@ services:
     networks:
       - proxy
     environment:
-      - "CPAD_MAIN_DOMAIN=$DOMAIN"
-      - "CPAD_SANDBOX_DOMAIN=sandbox.$DOMAIN"
+      - "CPAD_MAIN_DOMAIN=${DOMAIN}"
+      - "CPAD_SANDBOX_DOMAIN=sandbox.${DOMAIN}"
       # Traefik can't use HTTP2 to communicate with cryptpat_websocket
       # A workaroung is disabling HTTP2 in Nginx
       - CPAD_HTTP2_DISABLE=true
@@ -27,9 +27,11 @@ services:
       labels:
         - "traefik.enable=true"
         - "traefik.http.services.${STACK_NAME}.loadbalancer.server.port=80"
-        - "traefik.http.routers.${STACK_NAME}.rule=Host(`${DOMAIN}`${EXTRA_DOMAINS})"
+        - "traefik.http.routers.${STACK_NAME}.rule=Host(`${DOMAIN}`, `sandbox.${DOMAIN}`${EXTRA_DOMAINS})"
         - "traefik.http.routers.${STACK_NAME}.entrypoints=web-secure"
         - "traefik.http.routers.${STACK_NAME}.tls.certresolver=${LETS_ENCRYPT_ENV}"
+        - "traefik.http.routers.${STACK_NAME}.tls.domains[0].main=${DOMAIN}"
+        - "traefik.http.routers.${STACK_NAME}.tls.domains[0].sans=sandbox.${DOMAIN}"
         ## Redirect from EXTRA_DOMAINS to DOMAIN
         #- "traefik.http.routers.${STACK_NAME}.middlewares=${STACK_NAME}-redirect"
         #- "traefik.http.middlewares.${STACK_NAME}-redirect.headers.SSLForceHost=true"