Tim Hunt

To do this, I have a file called test.php sitting in the root of my Moodle dev environment. I can put random code in there, and load the page in my browser, to see the result. Primitive, but it works. Currently, that file seems to contain

set_url('/test.php');
$PAGE->set_context(context_system::instance());

echo $OUTPUT->header();
print_object(userdate((new DateTimeImmutable("today 23:59", core_date::get_server_timezone_object()))->getTimestamp()));
echo $OUTPUT->footer();

Can you get any more information about that error?

If you open the Developer tools in your web browser, and swtich to the Network tab, you should be able to see that request being made to the server, and the resonse that comes back that triggers the error being displayed. The full details of that request and response might tell us more.