Navigate to your SharePoint page from a Private Browsing window (to open a Private Browsing window press cmd + shift + n from Safari). You should see this page informing you of an error and steps to resolve.
When you see the error message click the "Click here" button. A new window will open.
Once the new window has opened you should see the message in the accompanying screenshot. You can now close this window and return to your SharePoint page.