The error message “Unable to create directory uploads/2023/03. Is its parent directory writable by the server?” is typically caused by a permissions issue with the “wp-content/uploads” directory or its parent directory.

To fix this error, you need to make sure that the “wp-content/uploads” directory and its parent directories have the correct permissions. Here are the steps to do this:

1. Connect to your website using an FTP client or through the file manager in your hosting control panel.
2. Navigate to the “wp-content” directory and right-click on the “uploads” directory. Select “File Permissions” or “Permissions” from the menu.
3. Change the permissions for the “uploads” directory to “755”. This will give the directory owner full access, and other users will have read and execute permissions.
4. Check the box to apply for permission recursively to all files and subdirectories.
5. Click the “OK” or “Apply” button to save the changes.
6. Repeat steps 2-5 for the parent directory of “wp-content”.

If the above steps don’t work, you can also try changing the ownership of the directories to the same user that the web server is running under. This can typically be done through the command line using the chown command.

Once you have made these changes, try uploading a file again to see if the error has been resolved.