A component project manager escalates an issue regarding a key stakeholder to the program manager.

A component project manager escalates an issue regarding a key stakeholder to the program manager. The key stakeholder does not respond to emails or phone calls, and the project manager believes this key stakeholder is exhibiting a negative attitude toward the work. The key stakeholder has a significant influence over the component project, which could impact other components if delays occur. The program manager’s attempts to reach the stakeholder via email also fail.

What should the program manager do next?