If you are unable to link to an Unstack page, it may be possible that your page isn't published. This comes up often, so to double check that your page is live, please follow these steps.
Navigate to the website tab in your Unstack main menu and look at the "Status" column to find out if your page is live or in draft status.
If your page is in draft status, click the 3 dots symbol to the right of the page that is in draft to access it's settings.
Click "Save and Publish" to publish your page.
You should now be able to link to this page!