The list of sites and site collections appearing in the drop-down depends on the SharePoint search API. There are certain cases when a particular site is not displayed in the list.
If your environment is SharePoint On-Premise 2013 or 2016, check a step-by-step workaround in this article.
- If your environment is SharePoint 2019 or SharePoint Online (Office 365), please use the new connection feature available from version 188.8.131.52 and further. If you do not see this feature in your ShortPoint elements, please upgrade the version of ShortPoint using this tutorial and downloading the latest version from our official site.