The REST API test tool in Wordpress says that I have to move files before I can use channel management features, why?
The correct location for Jomres files is in the /public_html/jomres directory, and the REST API routing requires that location for it to function correctly.
In recent years many Wordpress hosting services have started making it so that plugins cannot write directly to the /public_html directory. To resolve this Jomres can install it's core files into the /wp-content/plugins/jomres/jomres directory and it will work fine except for the REST API.
If you need to use the REST API, using FTP you need to move the files in the public_html/wp-content/plugins/jomres/jomres directory to the public_html/jomres directory then empty the /public_html/jomres/temp directory.
Important : do not move any other files from the public_html/wp-content/plugins/jomres/ directory. Directories like "admin", "includes" , "public" and files like "jomres.php", "index.php" etc should remain in the same place, only the files under jomres/jomres should be moved.
Once you have made this change, double check the REST API test page. It should confirm that you can use the REST API now.