In the clarifications
This part is important
It can be difficult to prove the actual location of these markers, such as those under tree cover or not visible on street view. Submitters should make good use of the supporting text and photos when nominating and include when possible links to official sites in support of the nomination. Reviewers should also use clues such as trail and park maps to help.
It is really important to give enough information that means anyone can verify it is a trail and a marker on that trail at that place.
I’m not sure if I am seeing all of the description and supplementary text but it appears to be very minimal. It appears to be a marker about a beach and a simple statement that it is a trail marker.
Did you explain more about this? For example did the description say something about the trail where it goes from or to, is it short or long. In the supplementary did you explain that the symbol is for this trail and what is unique about this point that makes this marker significant. Was there a link to a website to back it up?
You can’t rely on only local reviewers who might instantly recognise it being the ones that will be deciding. For a marker that contains only a little information on it you need to fill in the gaps. When a marker contains a lot of information you will probably need less. This is the difference between the top and bottom of the acceptable examples in the clarification.
So I would suggest that you resubmit but with more information to help verify the trail, something that might link that trail to this marker and where it is.