mysqli::query(): Couldn't fetch mysqli

This error message is typically encountered when an attempt to execute a MySQLi query has failed. There are a few possible reasons why this error might occur:

  1. The MySQLi connection has not been established. Make sure you have connected to the database using the mysqli_connect() function before you try to execute a query.

  2. The MySQLi query is invalid. Make sure that you have written your MySQLi query correctly, and that it is valid MySQL syntax.

  3. The database server is down or there is a network issue that is preventing the connection to the database.

To troubleshoot this issue, you can try the following:

  1. Check the MySQLi connection. Make sure that you have established a valid connection to the database before you execute any queries.

  2. Debug the MySQLi query. Print out the query and verify that it is correct and that it is a valid MySQL statement.

  3. Check the status of the database server. Make sure that the database server is up and running and that there are no network issues that are preventing the connection to the database.

If you are still having trouble after trying these steps, please provide more information about your code and the context in which the error is occurring, and I would be happy to help further.