RE: Initializing application web client
There are a number of reasons this can happen:
1) Be sure that you don't see any security certificate errors when you log in. If you're using Internet Explorer, you'll see that the URL area turns red if there's a certificate error. The login won't be successful if you have a security certificate error. The most common cause for the certificate error is that you're using a self-signed certificate, but haven't imported the certificate onto the remote machine. The process for doing that is described in Appendix A of the Web Client Installation and Administration Guide.
2) You need to be able validate the security certificate used for the Runtime service. If you picked a different security certificate for the Runtime service than the one you used for the web site, you could run into an initialization error.
3) You need to be able to access the Runtime service. Sometimes firewall settings can prevent this. If you enter a URL like the following into the client browser, you should be able to access the XML document:
https://session_host_machine:48652/clientaccesspolicy.xml
Of course, you'll need to substitute your machine name into the URL.
4) Some people have had to install the DynamicsGPTrustedApp.msi to ensure that they had all of the needed security certificates. I haven't seen this problem myself, but others have reported it.
My guess is that your issue is the first one I listed.