diff --git a/dockerfiles/services/piwik/startup-piwik.sh b/dockerfiles/services/piwik/startup-piwik.sh
index 4decf3a1dc43a867bb9141590789e7b16cb130bd..4b5ba91c1621648ba150ea9c17f0bc973a277cac 100644
--- a/dockerfiles/services/piwik/startup-piwik.sh
+++ b/dockerfiles/services/piwik/startup-piwik.sh
@@ -73,7 +73,8 @@ then
   
   if [ -z ${SITE_URL+x} ]
   then
-    SITE_URL="http://${URL}"
+    PRIMARY_DOMAIN=`echo $URL | cut -d. -f2,3`
+    SITE_URL="http://${PRIMARY_DOMAIN}"
   fi
   
   if [ -z ${SITE_TIMEZONE+x} ]