'Edit this page' links do not work - can we replace it with 'date of last edit'?

We currently have three pages that are published through https://essif-lab.pages.grnet.gr/framework/, each having the text 'Edit this page' at their bottom, all of which link to a different (and wrong) location:

• Introduction links to facebook (https://github.com/facebook/docusaurus/edit/master/website/docs/introduction.md)
• Vision links to facebook 'page not found' (https://github.com/facebook/docusaurus/edit/master/website/docs/essif-lab-vision-and-purpose.md) and
• Functional Architecture also links to facebook 'page not found' (https://github.com/facebook/docusaurus/edit/master/website/docs/essif-lab-functional-architecture.md)

Can this be corrected