diff --git a/src/matrix/storage/idb/stores/SessionStore.js b/src/matrix/storage/idb/stores/SessionStore.js
index 25ea2351..6246169b 100644
--- a/src/matrix/storage/idb/stores/SessionStore.js
+++ b/src/matrix/storage/idb/stores/SessionStore.js
@@ -47,7 +47,7 @@ export class SessionStore {
 	}
 
     add(key, value) {
-        return this._sessionStore.put({key, value});
+        return this._sessionStore.add({key, value});
     }
 
     remove(key) {