When faced with a lack of responsiveness from a vendor, it is crucial for the project manager to address the issue directly and proactively. Inviting the vendor to a meeting allows for open communication and the opportunity to discuss and resolve the concerns. This approach aligns with best practices in vendor management and stakeholder engagement, which emphasize the importance of clear and purposeful communication, especially when issues arise that could impact project delivery. By discussing the concerns, the project manager and vendor can collaboratively identify the root causes of the lack of responsiveness and work towards a solution that ensures the project's success.
References: The answer is supported by best practices in vendor management, which suggest that direct communication is key to resolving issues and maintaining a successful partnership. The approach of inviting the vendor to a meeting is consistent with the principles outlined in the PMBOKGuide, which advocates for proactive stakeholder engagement and communication12. Additionally, the Professional in Business Analysis (PMI-PBA) materials highlight the importance of vendor analysis and relationship management as part of business analysis activities345.