The SOAP connection error may be caused by the following 2 situations:
(1) the MDM username and/or password may be invalid according to the rules for these username and/or password OR
(2) the WAS and/or DM co-server may be down or having problems. Please look in the Console logs for further information. They are stored on the following directory : %IBM_DIRECTOR_HOME%\logs.
Check the error logs and see if the Websphere Application Server is started. Also check if the MDM username / password are valid username / password on the operating system of the DM Co-server.