Wordpress Update or its plugin/theme installation fails: cURL error 28: Resolving timed out after 3512 millisecond

Symptoms

• Wordpress update or its plugin/theme installation fails with the following error:

  Warning: An unexpected error occurred. Something may be wrong with WordPress.org or this server configuration. cURL error 28: Resolving timed out after 3512 millisecond

• Trying to reach the WordPress.org website takes too long:

  # time wget WordPress.org
  
  real 0m5.180s
  user 0m0.020s
  sys 0m0.021s

• The following error can be found in the /var/log/plesk/panel.log file:

  CONFIG_TEXT: An unexpected error occurred.
  Something may be wrong with WordPress.org or this server’s configuration.

• Not possible to update Wordpress to latest version, showing as if it was already running on latest one.

• When attempting to upgrade Wordpress version, the following can be seen:

  Warning: Unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the <a href="https://wordpress.org/support/">support forums</a>. (WordPress could not establish a secure connection to WordPress.org. Please contact your server administrator.) in /var/www/vhosts/example.com/httpdocs/wp-includes/update.php on line 155 Warning: An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration.

• Some of the WordPress instances may be shown as Quarantined or Broken in the WordPressToolkit.

Cause

The configured name server in the /etc/resolv.conf file is answering in more than 3.5 seconds.

Resolution

Resolve the issue with the nameserver or switch to another faster nameserver, e.g. to the Google:

1. Connect to the server via SSH.

2. Open the /etc/resolv.conf file via any text editor and modify the nameserver directive:

   Before:

   CONFIG_TEXT: nameserver 203.0.113.2

   After:

   CONFIG_TEXT: nameserver 8.8.8.8