Without fail, there will be customers where executives are hesitant to engage.
There are a myriad of reasons for them to not engage that do not reflect on your team's executive presence. They could be looking for their direct report to manage the partnership, or they may not fully understand the type of value that you can create for them.
This is when outreach from you, as a senior leader, is needed to drive home the importance of their involvement and input on your partnership. Aligning with executives on partnership goals and overall expectations is the surest way to create a clear path to success for both your CSMs and their respective teams.