WordPress: Call to undefined function wp_embed_register_handler()

I have a WordPress website that is still under development. I was working on this website till end of Feb, 2021 and hold all works due to COVID crises. Till that date, website was working. Now I have resumed my work and just looking into website. But now, website is throwing an error "Fatal error: Uncaught Error: Call to undefined function wp_embed_register_handler()"

I have also crossed the file "wp-includes/embed.php" file in which this function exists and function is already defined before calling it. You can see attached screenshot of whole error tracing.

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I am not getting this error on all pages but almost every pages. I am not able to understand why I am getting this error even I have not touched anything on website from last 3-4 months. And it was working fine when I was working last.

Can someone please help on this? I am not very experienced in WordPress but have intermediate knowledge.

Thanks in Advance