We have been using SF identity for quite a few years.  Up until just recently it worked relatively well for both our Production sites and our Dev environments.  Sometime within the last few weeks / month? something has changed.   The connected app to log into our production website still works, however the connected app to log into our dev environments no longer works.   No changes have been made to the connected app or to the web code.   Rather than log into the secure side of the dev website the connected app takes the user to the public side and does not log into the site.   I now get the following error if i try to force the URL over to the private side of the site:

URL No Longer Exists

You have attempted to reach a URL that no longer exists on salesforce.com.

You may have reached this page after clicking on a direct link into the application. This direct link might be:

• A bookmark to a particular page, such as a report or view

• A link to a particular page in the Custom Links section of your Home Tab, or a Custom Link

• A link to a particular page in your email templates

If you reached this page through a bookmark, you are probably trying to access something that has moved. Please update your bookmark.

If you reached this page through any of the other direct links listed above, please notify your administrator to update the link.

If you reached this page through a link on our site, please report the broken link directly to our Support Team and we will fix it promptly. Please indicate the page you were on when you clicked the link as well as any other related information. We apologize for the inconvenience.

Thank you again for your patience and assistance. And thanks for using salesforce.com!

Any ideas on what may have changed or what my next steps are to troubleshoot?

Thanks mucho!