I think many others share your experience! Often we struggle to "crack the code" of some-one else. Below are three suggestions:
a) Using the DISC profile in a stepped approach. First ask yourself is he mostly an introvert (which puts him in the compliance / steadiness quadrants) or an extravert (which puts him in the dominance / influence quadrants). Then the second question to ask is whether he makes decisions mostly based on thinking (facts oriented - compliance or dominance) or feeling (people oriented - steadiness or influence)? That should give you his primary style (or what you think his primary style is). Also guess what his secondary style is Then you modify your approach and try things out until you get results. However, if you are already modifying your approach and you are still getting the same feedback from him, then it's time to try something different.
b) "First time" approach: In this approach, we treat the person (in our heads) as if we are meeting them for the very first time. And the past does not exist anymore! So we let go of any historic issues or misunderstandings, and pretend that they are a complete stranger. Often this help us to hear things more clearly, because our assumptions are not getting in the way. Then we need to behave towards them in a new way, whereby we listen carefully to everything they say, and then check our understanding every step of the way ("so are you saying that xxxx is a concern to you and that it could be fixed by yyyyy? Do I understand you correctly?)
c) Feedback approach: In this approach, you have a very direct discussion. You ask a question like "I get a lot of feedback from you that I interpret things you say in the wrong way. How do you feel that I misunderstand you?" What should I do differently to understand you better?
In answering this question I'm assuming that the person is genuinely seeking a connection with you and is open to discussion. For a relationship to work, it requires give and take on both sides and you should not hold back on making some requests of your own in order to make the communication flow. It's a two-way street!
Let me know if this helps or if we can support you further to get the results that you want. Our live coaching option also allows us to do a deeper dive into this issue.