HTTP 500 error keeps reoccuring

Hello,

I was using my WordPress website without any problems. Suddenly I get this HTTP 500 error. I don’t have access to my dashboard. I tried fixing it myself with the help of this website https://www.wpbeginner.com/wp-tutorials/how-to-fix-the-internal-server-error-in-wordpress/

No luck. I put back a backup and database backup that I knew it didn’t have any problems. I have access to my dashboard again but doesn’t matter what I do (go to pages, plugins, clicking any button), it goes back to the HTTP 500 error.

My hosting service says it’s calling a function that doesn’t exist
AH01071: Got error ‘PHP message: PHP Fatal
error:

Uncaught Error: Call to undefined function wp() in

/data/sites/web/dacostacbpapbe/www/wp-blog-header.php:16\nStack trace:\n#0

/data/sites/web/dacostacbpapbe/www/index.php(17): require()\n#1 {main}\n
thrown

in /data/sites/web/dacostacbpapbe/www/wp-blog-header.php on line 16’

I tried deleting that plugin, but still no change. All plugins are deactivated and still, the problem occurs.

I don’t know what to do to make it work.
If someone can help me with this, that would be awesome.

Thank you
Cynthia

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