We have all been here before. There is a person in the position to say "Yes" and sign on as a new client. It might be an individual account, but more likely it's a business. You might have made progress on the periphery, but all roads lead to someone who will not give you an appointment. You suspect they are not ghosting you, but your message and proposal has not been brought to this person's attention. Put another way, your priorities are not their priorities. What can you do?

You want to be tactful. This will not be an "I'll be back" moment from Terminator. It will not be the scene in the Liberty Mutual car wash commercial where the guy keeps talking as he keeps pace with the car going through the car wash. You want to get on the person's radar and be able to spend a moment with them. It might simply be a social moment, but the outcome is they connect a name with a face. Yours.

1. Where do they spend time outside work? Does anyone know their habits?  Do you have friends inside the company?  They may have a favorite sports bar, visiting on away game nights. You start going and become part of the regular crowd. Logic:  Here is an urban legend. It's been said one of the reasons London won the competition to host the 2012 Olympics was they had a team that assembled their proposal. They met the judging committee when they made their presentation. They learned what cities the judges would be visiting and the hotels where they would be staying. They would send a team member to that city and sit at the hotel bar. When one of the judges happened to walk in, they would say hello and strike up a polite social conversation. This kept them on the radar screen.
2. Offer financial planning with no monetary strings attached. A guy with a benefits firm was going after plan business in school districts within his state. He would call on the superintendent, explain what he does and make the following offer: He would do financial plans at no monetary cost for the senior district officials. The only thing he wanted in return was to be notified when the benefit plan was put up for competitive bidding. Logic: The bidding procedure needed to be made public through newspaper announcements, but at the time it might not have been the most widely read publications where the ads were placed. He got the opportunity to compete on a level playing field.   
3. Does your connection play golf? This could easily be tennis or squash. The important things is there is a sport you both engage in seriously. Ideally you belong to the same club or can be brought in as a guest at the right time. Logic:  Assuming you are paired up, it is common practice to get together for a drink or meal after a game. You get the opportunity to introduce yourself.
4. Have they recently received recognition? People win awards all the time, especially if they are involved in the community. People like to see their name in print. Get the newspaper article announcing the award, complete with the photo of the presentation. Bring it to a trophy shop, asking them to laminate it onto a presentation plaque. Take delivery and either ship or deliver it to them personally, following up afterwards. Logic:  This type of item is usually displayed on a wall of fame in their office. Once they win, they will want this plaque. Now they have it.
5. Who knows who? Can you find someone who can introduce you?  LinkedIn is a logical place to start. Enter their name and look for second level connections. Review the list. Start reaching out to them to determine the strength of the connection. Will they set up drinks or coffee for the three of you? Logic:  You have heard the expression "Six degrees of separation."  The logic is everyone has a line of connection to everyone else in the world through a maximum of six steps.
6. The most influential people in the world? There may be a reason why you need to reach someone who is the head of a Fortune 500 This is an expensive project undertaken at the highest levels at your firm. BoardEx is an example of a company specializing in data. One of their areas of expertise is interlocking board of director relationships. Based on the senior people the officials in your company know, they can determine who serves on the same board of directors at different companies with the person who is your target. Your higher up connection approaches them at the next board meeting, asking if they would agree to make time for your person. This is a very expensive service. Logic:  A CEO of a listed public company serves on their own board of directors, but they are often invited to serve on the board of other firms. The boards where the overlaps occur might not be immediately apparent.

Related: Getting through to hard-to-reach prospects: 8 strategies that actually work

They say persistence is a virtue. These are strategies that can put you in the right place at the right time. At that point, it's up to you.