Fatal error: Uncaught Error: Call to undefined function gmr_posted_on()
in /home/ns21.tube/htdocs/wp-content/themes/ns21/template-parts/content-single-attachment.php on line 35

Call stack:

1. require()
   wp-includes/template.php:812
2. load_template()
   wp-includes/template.php:745
3. locate_template()
   wp-includes/general-template.php:206
4. get_template_part()
   wp-content/themes/ns21/single.php:47
5. include('/home/ns21.tube/htdo...emes/ns21/single.php')
   wp-includes/template-loader.php:106
6. require_once('/home/ns21.tube/htdo.../template-loader.php')
   wp-blog-header.php:19
7. require('/home/ns21.tube/htdocs/wp-blog-header.php')
   index.php:17