Fatal error: Uncaught Error: Call to undefined method WP_Error::has_errors()

I tried to install a “NEVE” theme and got this error. Not knowing how to fix it. Please help how this can be fixed.
The goal I want to achieve is to bring back the theme I used before, namely the original WordPress theme 2017. Let me clarify that the problem happened the day before.
The places where are added dots “….” are from me.

Fatal error: Uncaught Error: Call to undefined method WP_Error::has_errors() in /home/…../addon_domains/…../wp-content/themes/neve/functions.php:81
Stack trace: #0 /home/…../addon_domains/…../wp-settings.php(425): include() #1
/home/…../addon_domains/…../wp-config.php(103): require_once(‘/home/concretec…’) #2 /home/…../addon_domains/…../wp-load.php(37): require_once(‘/home/concretec…’) #3 /home/…../addon_domains/…../wp-blog-header.php(13): require_once(‘/home/concretec…’) #4 /home/…../addon_domains/…../index.php(17): require(‘/home/concretec…’) #5 {main} thrown in /home/…../addon_domains/…../wp-content/themes/neve/functions.php on line 81