Clicking the icon in the Delivery Pipeline Plugin to run a manual step in a pipeline yields a "Cannot trigger build!" error. Running the manual step in Build Pipeline Plugin is successful (with either 1.4.2 or 1.4.3). Steps to reproduce:

• Create a pipeline with a manual step
• Run the pipe up to the manual step
• Click the icon to the the right of the manual step

In Chrome, this produces a popup with the error message shown in the attached image.