Steven Zahm@ Todd
1. The connections_templates folder is only there to support legacy templates, not for custom templates. Since templates are plugins, you need to put them in the plugins folder. And for WP to recognize it as a plugin, the template needs to have the plugin header added. If you trying to make a custom template from one of the core templates you’ll need to change all class and function names and will as the slug in the $atts array.
2. Make sure you are not copy/pasting option from the website. Delete the shortcode manually type the options and option values. Copy/pasting from the website will past in hidden HTML markup and/or fancy quotes neither of which the WP shortcode API supports when trying to parse the options.
3. If the user logged in with Link installed prior to have an entry in Connections, the user will not be linked. For example, user logins in, no match is found. The user is marked as being checked and will not be checked again. For testing. Create an entry in Connections, create a user, and then login as that user. Some membership plugins do break the linking process. Do you have any installed?
Hope that helps.