Wordpress issues

404 error for a page that opens in the editor

- Corruption in the [WP]_POSTS table index. Repair the table.

When saving a post, the message “You do not have sufficient previlliege to edit the post” appears

- Corruption in the [WP]_POSTS table index. Repair the table.

Core does not update, plugins do not install, and media files do not upload

WP 7.2.1 hosting at freehost.com.ua. Symptoms: the core update stops during unpacking; plugins are uploaded to TMP but not unpacked; media files are uploaded to the server (wp-content/uploads/year/month) but do not appear in the database; enabling all DEBUG options did not help; enabling PHP logs produced no errors, and the provider did not enable them. I found several @error\_reporting( 0 ); lines in a plugin. How can anything be found like this? Solution: I think libraries are missing or the version is wrong, but I did not determine which ones. The issue was resolved after switching PHP to 7.1 at the provider. Versions 5.3 and 5.6 did not help. I did not compare modules.