Error while checking for update: An error occured while sending the request
Check the event log of the Exchange Server Toolbox or the Windows Event Viewer under Windows Logs | Application for the following message:
"The request was aborted: Could not create SSL/TLS secure channel"
If this is present, you can fix the problem this way:
You can now copy the contents of the text box under Options | SSl Encryption Collections into a text document. Append the following keys at the end:
Follow the editing instructions in the right part of the window under "Help".
Then copy the text back into the text box and press "Apply" to save the settings. For the changes to be applied, you must restart the server.