Download link is throwing error

Hi
when the system sends an email to the recipient with the ebook download link, the link is opening with an error!

“There has been a critical error on your website”

I have enabled debugged more and the error is this:
Fatal error: Uncaught Error: Call to undefined function mime_content_type() in /home/r2mhomeloan/public_html/wp-content/plugins/download-after-email/includes/download.php:80 Stack trace: #0 /home/r2mhomeloan/public_html/wp-includes/class-wp-hook.php(287): dae_download_file(”) #1 /home/r2mhomeloan/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) #2 /home/r2mhomeloan/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #3 /home/r2mhomeloan/public_html/wp-settings.php(546): do_action(‘init’) #4 /home/r2mhomeloan/public_html/wp-config.php(85): require_once(‘/home/r2mhomelo…’) #5 /home/r2mhomeloan/public_html/wp-load.php(37): require_once(‘/home/r2mhomelo…’) #6 /home/r2mhomeloan/public_html/wp-blog-header.php(13): require_once(‘/home/r2mhomelo…’) #7 /home/r2mhomeloan/public_html/index.php(17): require(‘/home/r2mhomelo…’) #8 {main} thrown in /home/r2mhomeloan/public_html/wp-content/plugins/download-after-email/includes/download.php on line 80

Can you please help me with this issue? I like your plugin!

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