New user register page controller not working

I’ve just turned on new user registration on a site I’m setting up.
Tried running through the sign-up, but when I hit submit I get the following error;


                    if ($config->get('')) {
                        if (Config::get('')) {
                            $fromName = Config::get('');
                        } else {
                            $fromName = t('Website Registration Notification');
                        $mh->from(Config::get(''), $fromName);

"Class "Concrete\Controller\SinglePage\Config" not found"

Anyone able to point me in the right direction for fixing this? Would’ve thought it should work right out of the box; I haven’t changed the login/register pages at all.

This error doesn’t occur unless the email settings are checked in the account registration settings; no verification/no admin email = no problem.

I’ve tried the 9.2 update as the bug fixes there include ‘Fixed error registering users with email validation under PHP 8.’, but that hasn’t fixed this error.

In case anyone stumbles across this with the same issue, it’s been addressed here;