Warning: Parameter 2 to qtranxf_postsFilter()

Hi,

I faced this problem after migrating my website to new domain:

Warning: Parameter 2 to qtranxf_postsFilter() expected to be a reference, value given in /www/htdocs/w014f8ca/uds2.books-and-other-stuff.net/wp-includes/class-wp-hook.php on line 286

The problems can be seen on the front-end, but not on the back-end

Any suggestion to solve the problem?

Here the Link:
https://uds2.books-and-other-stuff.net/de/