diff --git a/lam-packaging/docker/start.sh b/lam-packaging/docker/start.sh
index 0f563daa..f1b21bd7 100755
--- a/lam-packaging/docker/start.sh
+++ b/lam-packaging/docker/start.sh
@@ -23,7 +23,7 @@
 set -eu # unset variables are errors & non-zero return values exit the whole script
 [ "$DEBUG" ] && set -x
 
-if [ "$LAM_DISABLE_TLS_CHECK" == "true" ]; then
+if [ "${LAM_DISABLE_TLS_CHECK:-}" == "true" ]; then
   ln -s /etc/ldap/ldap.conf /etc/ldap.conf
   echo "TLS_REQCERT never" >> /etc/ldap/ldap.conf
 fi