The following error is thrown when attempting to connect to CA PPM using the SOAP UI: 

CMN-10011: Please enter a valid User Name and Password. Note that the Password is case-sensitive

However, the same username and password work when logging into the OnDemand portal.

CA PPM SaaS

A user that does not exist in the OnDemand portal must be used to connect to PPM using SOAP, or XOG in general. If a non-portal user does not exist in the PPM application, one can be created from Administration - Resources. The username and password created for this user will then be what is used to login using SOAP/XOG. It is recommended that this user be granted all access rights in order to not run into any access issues when performing a XOG read/write.

If a Portal user is used Navigate to Administrator -> Resources -> Resource name and save the same password as the one configured for Portal Login.