1. Click Start, point to Programs, click Administrative Tools, and then click Internet Services Manager.
2. Click your server, and then expand the Web site that contains the Exadmin virtual directory. The default Web site is "Default Web Site."
3. Right-click the Exadmin virtual directory, and then click Properties.
4. Click the Directory Security tab.
5. Under Secure Communications, click Edit.
6. Click to clear the Require secure channel (SSL) check box. If the Require 128-bit encryption is selected and greyed out, make sure to select Require secure channel (SSL) and deselect Require 128-bit encryption. Then deselect Require secure channel (SSL) again.
7. Click OK twice.
8. Close Exchange System Manager, and then reopen it.