The function it’s looking for is a core WP function. This function is located in the file /wp-includes/formatting.php. Either the file is missing or the file is corrupt. Try reinstalling WP on your site.
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ACF wouldn’t be so widely used in WordPress if it didn’t have some pretty amazing capabilities. In this article, we look at a few of the features we’ll discuss during “7 things you didn’t know you could do with ACF” at #WPEDecode later this month. https://t.co/5lnsTxp81jpic.twitter.com/Yf0ThPG1QG