Hi and thanks for the replies! Sorry I haven’t been able to get back to this. Other projects have taken up the time of playing around with new ideas, some of which would make use of the Shorten URL plugin.
“Post name” refers to the option that is called “Post name” under the WP-Admin > Settings > Permalinks page (/wp-admin/options-permalink.php), section Common Settings, the last of the five preset options before the Custom Structure option. The example value for this setting is [BLOG-URL]/sample-post/.
After a bit of re-testing, I’d say there’s a chance that the problem was caused by not having https:// in the beginning of the links. Thanks for the tip! It might be a good idea to have a reminder of this on the page /wp-admin/admin.php?page=shorten-url/shorten-url.php near the “Add a new URL to shorten” button. Or even better, to automatically add https:// in the beginning of links that don’t have :// in them or do not start with / and to notify the user when this was done, giving the option to save the redirection with the exact URL the user typed.
In other words, typing google.com in the external redirection URL would create a redirection to https://google.com, show a notification that https:// was added in the beginning of the URL, and give you a clickable link that would correct the redirection to be to google.com instead, in practice leading to the page [BLOG-URL]/google.com. The odd user who wants to serve a page, image or anything at this URL would get it done conveniently, while everyone else with a more common use case would avoid the 404 errors.
