Before you attempt to sell to the senior executive you need to find out from his team why they wouldn't buy it. The senior executive will defer to his team prior to making the decision to purchase so you're only assuring your failure by contacting him at this point.

Treat him like any other customer. Don't be intimidated by him or his position. I know it is a short answer but honestly that is the best thing you can do. He will see right through you if you do anything else.

You have reached out to him for advice, then definitely start from there. Given his executive experience, he probably has the background and network to give you valuable feedback. You could focus your feedback gathering about your product, market fit, potential customers, pricing etc which will help your understand if he might be interested to try/buy it.

I would say you have nothing to loose and only to gain from the conversation. Maybe you may not be able to sell him today, but you walk away with advice and possible connections/referrals

I think you want to go into this meeting with the expectation that you are there to continue to build the existing relationship you have and that you would like to gain any tips or tricks he might have as you are launching your business. Maybe the ask in this situation is around if he can be a referral for you when you met the right client or maybe you ask if his team could to give your software a try for a few months for more feedback. I wouldn't try to sell this guy quite yet. Let it happen organically as a result of him trusting you and trying to help you.

Don't confuse yourself or the customer.
It goes back to your objective of the meeting. Different objectives may set different way and intonation of discussion. If your objective is to sell the solution, you may need to prepare the relevant sales kit. If you set the right expectation, it will be much easier for you to navigate the discussion.

For meeting senior executives, it is always good to know the company information, his profile, who is he in the company, what he have done or future projects.. but as our friend Jacob said.. Don't be intimidated by him or his position.

Cheers

1. First be sure you know how to ask good questions.
2. Then frame a series of question for learning how they create value from software.
3. Learn what they like and don't like about their current software solutions.
4. Ask him/her to describe what a better software solution would look like and why.
5. Determine what barriers they have to adopting new software for their firm and why these barriers exist and how much it would cost to overcome them.
6. Ask how you can help the firm overcome any barriers to adoption but focus on the "lowest barrier" first.
7.etc

Once you've framed what their problems are you can begin to position how your software can solve just 1 and only 1 problem more effectively and get them to buy something you know will work well. Be sure you work closely with the firm's team to have a good introduction.

Finally never negative sell what they use today and emphasize why your offering is desirable.

We in supply chain always facing such problems. Customer will praise solution but, will not buy it. One customer is very near to our ICD, they even successfully had a trial movement from our facility but, later on refused to take our services. In such case your networking became important. Here are some tips:
1. By using your network just try to find out which solution actually they are utilizing.
2. Note down the requirement they will having by discussion with his team.
3. Try to know the main reason of refusal(20% reasons gives 80% result). They may have long term contract agreement with prevailing solution provider at better attainment cost.
4. Have a mind image simulation i.e put your self on the seat of team and figure out your software.
5. On meeting do not directly discuss over your software and it's benefit. Try to know his views and then give them counter offer.
Here is solution of every problem if we look at problem in the eye of customers.
Have a complete preparation with confident meeting!