In the Lab Management project (“LAB_PROJECT” project in “DEFAULT” domain available in http://<server>:<port>/qcbin/start_a.jsp?projectType=LabManagement) of Application Lifecycle Management (ALM), one of the configurations required for allowing integration of Performance Center (PC) server with ALM server is in the ALM Connection button available in the Servers\PC Servers module. In ALM12.0x\PC12.0x, using this button more than once to set a valid and available URL of ALM server will cause a popup error message: “Host is unreachable. Please ensure that host’s name is correct.”
This is a defect in PC12.0x.
If there is a need to reset this ALM Connection settings after having it already changed in the same ALM session, it is recommended to logout and login back from the Lab Management project and then try to reset ALM Connection settings (it is recommended to avoid changing this setting more than once in a single ALM session).