Archive page cannot be overwritten

I would like to create a landing page for our nonprofit organization’s annual fund giving page at https://careyinstitute.org/2017 . I could not do this before since there was an automatic archive page set up at this address, so I downloaded and installed this plugin. The plugin deactivated the archive page, and now when I go to https://careyinstitute.org/2017 I get a 404 error as one might expect. However, when I attempt to create a new page at https://careyinstitute.org/2017 the page publisher automatically changes the URL to https://careyinstitute.org/2017-2. Is there a workaround to get rid of the “-2” at the end of my url so I can use my desired URL for the landing page? Thank you!

The page I need help with: [log in to see the link]