Using essential_v5.11.2_2022-07-18_20-24-25 with https://www.thesciencecouncil.com/ in Joomla!3 works perfectly.
I've upgraded the site to Joomla!4 as https://bak.thesciencecouncil.com/. All works except Newsletters/Newsletter Archive which shows "0 Class 'JDispatcher' not found "
Please, raise a support ticket (https://www.acymailing.com/support/) for this so we can further assist you.
Thanks. I've raised a ticket.