diff --git a/packages/openactive-openid-test-client/lib/browser-automation-for-auth.js b/packages/openactive-openid-test-client/lib/browser-automation-for-auth.js
index b329828e68..70487db0f8 100644
--- a/packages/openactive-openid-test-client/lib/browser-automation-for-auth.js
+++ b/packages/openactive-openid-test-client/lib/browser-automation-for-auth.js
@@ -32,7 +32,7 @@ const AUTHORIZE_SUCCESS_CLASS = 'openactive-test-callback-success';
 async function addScreenshot(page, title, context) {
   const image = await page.screenshot({
     encoding: 'base64',
-  }).toString();
+  });
   const url = page.url();
   context.screenshots.push({
     title,