Hi @hartu
Did you call the the_field() function outside The Loop section? If you did, you need to provide the ID of the post/page as the second parameter like this:
<?php the_field( "anzeige", 99 ); ?>
Where 99 is the ID of your post/page that has the custom field. This page should give you more idea about it: https://www.advancedcustomfields.com/resources/the_field/.
Hope this helps.
