TYPO3 Core

Until TYPO3 v 12.4 it was possible to define a page title provider like this in TypoScript:

    config.pageTitleProviders {
        beratungsstelle {
            provider = \MyVendor\MyExtension\PageTitle\PageTitleProvider
            before = record
            after = altPageTitle
        }
    }

In 13.4 an error is thrown:

You have requested a non-existent service "\MyVendor\MyExtension\PageTitle\PageTitleProvider". 
Did you mean this: "MyVendor\MyExtension\PageTitle\PageTitleProvider"?

I would suggest that we trim for a backslash at the start in

/var/www/html/vendor/typo3/cms-core/Classes/PageTitle/PageTitleProviderManager.php line 59

And possibly test the existence of the Service before using it so that we can give better error messages.

Removing the slash at the start of the3 FQNC solves the ptoblem