diff --git a/readme-vars.yml b/readme-vars.yml
index 0593181..9bceee0 100644
--- a/readme-vars.yml
+++ b/readme-vars.yml
@@ -36,6 +36,7 @@ param_env_vars:
   - { env_var: "MONGO_PORT", env_value: "27017", desc: "Mongodb Port. Only evaluated on first run." }
   - { env_var: "MONGO_DBNAME", env_value: "unifi", desc: "Mongodb Database Name (stats DB is automatically suffixed with `_stat`). Only evaluated on first run." }
   - { env_var: "MONGO_TLS", env_value: "true", desc: "Mongodb enable TLS. Only evaluated on first run." }
+  - { env_var: "MONGO_AUTHSOURCE", env_value: "admin", desc: "Mongodb authSource. For Atlas set to `admin`.Defaults to `MONGO_DBNAME`.Only evaluated on first run." }
 
 # optional container parameters
 opt_param_usage_include_env: true
diff --git a/root/defaults/system.properties b/root/defaults/system.properties
index c665429..b06370d 100644
--- a/root/defaults/system.properties
+++ b/root/defaults/system.properties
@@ -41,6 +41,6 @@
 # unifi.throughput.port=6789
 #
 db.mongo.local=false
-db.mongo.uri=mongodb://~MONGO_USER~:~MONGO_PASS~@~MONGO_HOST~:~MONGO_PORT~/~MONGO_DBNAME~?tls=~MONGO_TLS~
-statdb.mongo.uri=mongodb://~MONGO_USER~:~MONGO_PASS~@~MONGO_HOST~:~MONGO_PORT~/~MONGO_DBNAME~_stat?tls=~MONGO_TLS~
+db.mongo.uri=mongodb://~MONGO_USER~:~MONGO_PASS~@~MONGO_HOST~:~MONGO_PORT~/~MONGO_DBNAME~?tls=~MONGO_TLS~&authSource=~MONGO_AUTHSOURCE~
+statdb.mongo.uri=mongodb://~MONGO_USER~:~MONGO_PASS~@~MONGO_HOST~:~MONGO_PORT~/~MONGO_DBNAME~_stat?tls=~MONGO_TLS~&authSource=~MONGO_AUTHSOURCE~
 unifi.db.name=~MONGO_DBNAME~
diff --git a/root/etc/s6-overlay/s6-rc.d/init-unifi-network-application-config/run b/root/etc/s6-overlay/s6-rc.d/init-unifi-network-application-config/run
index bc9c3d0..3ad6985 100755
--- a/root/etc/s6-overlay/s6-rc.d/init-unifi-network-application-config/run
+++ b/root/etc/s6-overlay/s6-rc.d/init-unifi-network-application-config/run
@@ -34,6 +34,11 @@ if [[ ! -e /config/data/system.properties ]]; then
         else
             sed -i "s/~MONGO_TLS~/false/" /defaults/system.properties
         fi
+        if [[ -z "${MONGO_AUTHSOURCE}" ]]; then
+            sed -i "s/~MONGO_AUTHSOURCE~/${MONGO_DBNAME}/" /defaults/system.properties
+        else
+            sed -i "s/~MONGO_AUTHSOURCE~/${MONGO_AUTHSOURCE}/" /defaults/system.properties
+        fi
         cp /defaults/system.properties /config/data
     fi
 fi