Customer did some troubleshooting with v10.7 and was then advised to upgrade to 10.8 again and did some further troubleshooting and followed recommendations to install the cert but this is still not working.
Change the following:
introscope.webview.enterprisemanager.rest.base=https://<example.com>:8081/apm/appmap
To:
introscope.webview.enterprisemanager.rest.base=http://<example.com>:8081/apm/appmap
Also, reset back to the original settings on EM and Webview.