diff --git a/src/platform/web/worker/main.js b/src/platform/web/worker/main.js
index 41cf3419..db8d84e9 100644
--- a/src/platform/web/worker/main.js
+++ b/src/platform/web/worker/main.js
@@ -149,7 +149,7 @@ class MessageHandler {
             const newSession = new this._olm.Session();
             try {
                 account.unpickle("", accountPickle);
-                newSession.create_outbound(account, newSession, theirIdentityKey, theirOneTimeKey);
+                newSession.create_outbound(account, theirIdentityKey, theirOneTimeKey);
                 return newSession.pickle("");
             } finally {
                 account.free();