This can be caused if the domain is set to be a restricted site in the
registry even though it is not listed in Internet Explorer options.
-- Check the following key.
-- HKCU\software\microsoft\windows\CurrentVersion\int ernet
sttings\zonemap\domains
-- If a domain has been added to the trusted or restricted site it will
appear under Domains as a subkey, for example "hotmail.com"
-- If the domain is a trusted site it will have a value of 0x00000002 (2)
-- If it is a restricted site it will have a value of 0x00000004 (4)