diff --git a/mattermost/hooks/postgres_database-relation-joined b/mattermost/hooks/postgres_database-relation-joined
index 5122349..7c0e0ef 100755
--- a/mattermost/hooks/postgres_database-relation-joined
+++ b/mattermost/hooks/postgres_database-relation-joined
@@ -18,8 +18,10 @@ services:
       MM_USERNAME: $USER
 "
 
-sed -ri  's/(^\s+"DataSource": "postgres:[^:]+:)([^@]+)@/\1'"$PASSWORD"'@/' \
-    "$SERVICE_CONFIGSTORE/mattermost/config/config.json" || exit 1
+if [ -e "$SERVICE_CONFIGSTORE/mattermost/config/config.json" ]; then
+    sed -ri  's/(^\s+"DataSource": "postgres:[^:]+:)([^@]+)@/\1'"$PASSWORD"'@/' \
+        "$SERVICE_CONFIGSTORE/mattermost/config/config.json" || exit 1
+fi
 
 [ "$control" == "$(relation-get control 2>/dev/null)" ] && exit 0