diff --git a/database/mongodb.py b/database/mongodb.py
index 4924ca1..10852e2 100644
--- a/database/mongodb.py
+++ b/database/mongodb.py
@@ -25,7 +25,7 @@ def __init__(self, configuration: ConfigurationMongoDB):
         connection_url = 'mongodb://'
 
         if '' != configuration.username and '' != configuration.password:
-            connection_url += '${0}:${1}@'
+            connection_url += '{0}:{1}@'
 
         connection_url += configuration.host + ':' + str(configuration.port)