You can try restarting the IIS Admin Service. It works for me to solve the "Page cannot be displayed" problem.

Open regedit and go to: \HKEY_LOCAL_MACHINE\SOFTWARE\Cisco Systems, Inc.\System Info\OS Image (for original OS installation)or \HKEY_LOCAL_MACHINE\SOFTWARE\Cisco Systems, Inc.\System Info\OS Upgrade (if you had upgraded from the original installation...

SCCP signalling port for Cisco IP Phones is 2000.

Yes it does.

Also check if dialplan-pattern 1 9XXX83... extension-length command is enabled under telephony-service. This is required for DID numbers where CME will strip the full number and dial only the last number of digits specified in extension-length.