Have you ever got this error? While this happens, you must make sure you have configured your wp-config.php. Check for these line:
/** MySQL database username */
/** MySQL database password */
/** MySQL hostname */
Above is taken from wp-config-sample.php file. As long as you have configured the DB_NAME, DB_USER and DB_PASSWORD correctly, you should be fine. Some host might use a different DB_HOST, but mostly worked fine with localhost.
Well, if it does configured correctly and there still the same error happen, you might need to check the wp_options table.
Open the wp_options table using PHPMyAdmin or other similar software. Find the value siteurl in column option_name, if you see the option_value get a blank value like below:
Then you are probably on right track. Edit this row and insert your domain full URL in the option_value. Save.
Hopefully the error will go away. I don’t know why this could happen, but it did happen in one of my client website… 🙂 It’s indeed frustating to look for this error, since WordPress didn’t give any specific information about it.
If you found another cause of this error, please share.