"Unsafe JavaScript" error when trying to implement "Send a Report"

Hi! I'm trying to implement a scheduled set of Message Center reports to a list of recipients. I'm following this guide:

https://experienceleague.adobe.com/docs/campaign-classic/using/automating-with-workflows/use-cases/monitoring/sending-a-report-to-a-list.html?lang=en

However, my JavaScript activity is failing with this error:

03/08/2022 11:42:44 Unsafe JavaScript attempt to access frame with URL about:blank from frame with URL file:///usr/local/neolane/nl6//bin/htmlToPdf.js. Domains, protocols and ports must match.

Any idea how to resolve this? Thanks!