diff --git a/install-mm3.sh b/install-mm3.sh
index ec144d1..f807cb0 100755
--- a/install-mm3.sh
+++ b/install-mm3.sh
@@ -51,6 +51,7 @@ sed -i "s|TIME_ZONE =.*|TIME_ZONE = '$TIMEZONE'|g" /etc/mailman3/mailman-web.py
 sed -i "s|localhost.local|$FQDN|g" /etc/mailman3/mailman-web.py
 sed -i 's|postorius@{}|webmaster@{}|g' /etc/mailman3/mailman-web.py
 sed -i 's|root@{}|webmaster@{}|g' /etc/mailman3/mailman-web.py
+sed -i "s|^POSTORIUS_TEMPLATE_BASE_URL.*|POSTORIUS_TEMPLATE_BASE_URL = 'https://$FQDN/mailman3/'|g" /etc/mailman3/mailman-web.py
 echo "" >> /etc/mailman3/mailman-web.py
 echo "# fix retry must be larger than timeout error" >> /etc/mailman3/mailman-web.py
 echo "Q_CLUSTER = {" >> /etc/mailman3/mailman-web.py