Generating a Service Desk webservice call is able to establish a connection, but the following exception is returned: "INVALID AHD03055:Data partition Create restriction on Issue"
This error would normally indicate that the account being used to connect to Service Desk belongs to a Role which is subject to a Data Partition that effectively stops an Issue from being created.
Check the Data Partition 'Employee' for some examples. By default in the Employee data partition a 'Create' Data Partition exists against the Issue object, with the constraint 'id=1' - which can never be met - and so prevents anyone connected with the role Employee from creating an Issue.
Try configuring the userid in Service Desk Manager with the Access Type 'Administrator' and verify that the Administrator access type has the Role 'Administrator' as its default role.