As you can see, the getimagesize() and exif_imagetype() functions are from the WordPress core and PHP core, respectively. The main reason is that the server refuses the connection to open the file.
For a temporary solution, until you fix the issue, you can turn off debugging by changing the WP_DEBUG variable to false in wp-config.php.
For more information regarding debugging in WordPress, please visit this link: https://wordpress.org/support/article/debugging-in-wordpress/
We strongly suggest you contact your hosting support about this. They should be able to help you regarding this issue.
