Tim
1
If you are unable to post to your WP blog using an App Password, you might need to install the WP basic auth plugin.
The plugin is located here:
How to install basic auth plugin
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Download plugin zip
Click Code
Download ZIP
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Save file to hard drive
The file appears as Basic-Auth-master.zip
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Upload to WP blog
Upload and enable [Basic-Auth-master.zip]
If you are still unable to post, you can try going back to the original WP admin/password and renaming your xmlrpc.php file.