TYPO3 Exception 1504804727

Note

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[10.4] - [9th April 2021]

Situation

The TYPO3 backend throws an exception, when I click on Extensions.

(1/1) #1504804727 RuntimeException

This module "tools_ExtensionmanagerExtensionmanager" is only available as system maintainer
in /foo/bar/typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 464

Solution

The currently logged in backend user has been removed from the system maintainers list. Ask for access to be granted again by a backend user who is a system maintainer. Any system maintainer may grant access to other users.