Fixing WordPress update error

Output data:

1. PHP version: 7.4
2. WordPress version: 5.7.12
3. Hosting: Turbo NVMe (DirectAdmin panel).
4. Website theme: GeneratePress (do not update the theme as it may disrupt the design).
5. Plugins:

• The list of plugins is visible in the screenshot, including:
  • Elementor + Elementor Pro
  • Essential Addons for Elementor
  • JetElements For Elementor
  • LiteSpeed Cache
  • Yoast SEO
  • Polylang
  • Smush
  • Lazy Load - Optimize Images
  • Additional plugins (full list in the screenshot).
• Some plugins have warnings about incompatibility.

6. Website: The test version is hosted on a separate test domain, closed to indexing (to avoid negative impact on the main site).

Access: Full access will be provided to:

6. WordPress admin panel
7. FTP/SFTP
8. Hosting control panel
9. MySQL databases

Problem:

6. When trying to update WordPress or plugins, the following errors occur:
   • "Another update is currently in progress."
   • "Upload failed. Unauthorized"
   • "Update failed."
7. Manual WordPress updates are possible, but inconvenient for regular use.
8. Updating the website theme leads to a complete breakage of the design, so selective updating is necessary.

Task:

1. Fix the issue preventing automatic updates of WordPress and plugins.
   • Ensure the ability to update WordPress and plugins through the admin panel, without using manual file updates via FTP.
   • The fix should be implemented in such a way that it does not disrupt the operation of the site.
2. Maintain the functionality of the test site:
   • Do not update the theme if it will break the site.
   • All changes must be tested on the test version to eliminate the risk of breaking the main site.
3. Prepare documentation:
   • Describe what specific changes were made.
   • Explain how to apply these changes to the main site.
   • Provide recommendations for further support of update functionality.
4. Perform diagnostics:
   • Identify and resolve the root cause of the errors ("Unauthorized", "Another update is currently in progress").
   • Check all possible causes (permissions, server configuration, PHP limits, REST API, DNS, etc.).
5. Ensure selectivity of updates:
   • After the fix, ensure that WordPress can update plugins and the core without affecting the theme.

Execution requirements:

1. Quality and security:
   • Changes must not affect the functionality of the site.
   • Modifying the WordPress core or plugin files is prohibited unless discussed in advance.
2. Diagnostics:
   • Provide a report on what the problem was and how it was resolved.
3. Testing:
   • After the fix, check the possibility of automatic updates on the test site.
   • Ensure the site's functionality after each update.
4. Documentation:
   • Provide detailed instructions describing the changes so they can be replicated on the main site.

Acceptance criteria:

1. Automatic updates of WordPress and plugins work without errors.
2. The test site maintains functionality after all fixes.
3. A detailed instruction for applying changes to the main site is provided.
4. A brief test after the fix to demonstrate the functionality of automatic updates.