Use of undefined constant THEME_NS – assumed ‘THEME_NS’

Hi together,

I can not access my wordpress anymore. Not the visitor url and also not the Admin page. I receive error 500.

The logs telling me:

[01-May-2023 10:12:03 UTC] PHP Warning: Use of undefined constant THEME_NS – assumed ‘THEME_NS’ (this will throw an Error in a future version of PHP) in WordPress_01/wp-includes/widgets.php on line 5

[01-May-2023 10:12:03 UTC] PHP Fatal error: Uncaught Error: Call to a member function has() on null in WordPress_01/wp-includes/l10n.php:1270

I don’t have any ideas how to fix. I tried wo rename the plugin folder and also the theme. Nothing helped. Any ideas?

THANKS A LOT

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