According to the PMBOK Guide, 6th edition, one of the key skills of a project manager is to negotiate with stakeholders to achieve project objectives and balance the competing project constraints. Negotiation is also a tool and technique for the process of Manage Stakeholder Engagement, which aims to ensure that stakeholders' needs and expectations are met or exceeded. By engaging in creative and iterative negotiations with the leaders of each entity, the project manager can foster collaboration, trust, and commitment among the parties involved in the project, and ensure that the launch date is acceptable and feasible for all. This will increase the likelihood of timely and successful adoption of the new solution by the entire organization. References: PMBOK Guide, 6th edition, pages 53, 513-514, 518.

According to the PMBOKGuide, 7th edition, an issue is a point or matter in question or in dispute, or a point or matter that is not settled and is under discussion or over which there are opposing views or disagreements1. Issues can arise from various sources, such as changes, risks, defects, conflicts, or assumptions1. Issues can affect the project performance, scope, quality, schedule, cost, or stakeholder satisfaction1.
An issues log is a project document used to capture and track issues until they are resolved1. The issues log typically contains information such as the issue description, priority, owner, status, resolution, and impact1. The issues log is updated throughout the project life cycle as new issues are identified, analyzed, and resolved1.
In this scenario, the newly assigned project manager is informed by a few key stakeholders that the project has some serious issues. The first thing that the project manager should do to understand the issues is to review the issues log to ensure the issues are captured. This will help the project manager to get an overview of the current state of the project, and to identify the nature, scope, and impact of the issues. It will also help the project manager to verify if the issues have been properly documented, prioritized, and assigned to the responsible parties. Reviewing the issues log will also enable the project manager to plan the next steps to address the issues, such as communicating with the stakeholders, performing root cause analysis, implementing corrective actions, or escalating the issues if needed1.
The other options are not as effective as option B. Option A, escalating the issues to the project sponsor, may be necessary if the issues are beyond the project manager's authority or control, but it is not the first thing to do. The project manager should first review the issues log to understand the issues and their implications, and then decide if escalation is required or not. Option C, checking the risk management plan to ensure there is a strategy to address the issues, may be helpful, but it is not sufficient. The risk management plan provides guidance on how to manage risks, not issues2. Risks are uncertain events or conditions that may have a positive or negative effect on the project objectives, while issues are certain events or conditions that have already occurred and have a negative effect on the project performance1. Therefore, the risk management plan may not cover all the issues that the project faces, and the project manager should review the issues log instead. Option D, asking the key stakeholders to discuss the issues with the project team, may be beneficial, but it is not the first thing to do. The project manager should first review the issues log to get a clear picture of the issues, and then facilitate the discussion between the stakeholders and the team to resolve the issues.
: 1: PMBOKGuide, 7th edition, page 101 2: PMBOKGuide, 7th edition, page 113

A stakeholder engagement plan (SEP) documents how involved and influential your project stakeholders are. It also outlines your stakeholder communication plan, including when you'll reach out to each stakeholder, what platform you'll use, and how much information you'll deliver1. The project manager should assess the information requirements of the community to ensure effective communication and engagement.
This involves understanding what information the community needs, how they prefer to receive it, and how often they need updates. This approach helps to build trust, manage expectations, and foster a positive relationship with the community, which can contribute to the success of the project1. References: Asana Resources | Project management | 5 steps to creating a stakeholder engagement plan

In an agile environment, the servant leader's role is to facilitate the team's work and remove any obstacles or impediments that might hinder their progress2. If a deliverable is not being taken by the certifying team for many months, it represents an impediment to the project's progress. The servant leader should review the process and work to remove this impediment2. This could involve facilitating communication between the two teams, adjusting the process, or finding alternative solutions2. The goal is to ensure that the team can continue to deliver value and meet the project's objectives2. References: 2 10 Principles of Servant Leadership (With Examples) - Indeed2, When Servant Leadership Will Not Work - Modern Servant Leader3