It's sad when a fanfic gets forgotten. In the case of one about Percy Jackson and Travis Stoll, it could be that it was part of a smaller sub - genre within the fandom that just didn't gain enough traction. Like, if it focused on a very specific aspect of their relationship or a particular adventure that wasn't as appealing to the general Percy Jackson fan base. Maybe it lacked the action or the emotional depth that most fans are looking for in a fanfic.
A forgotten fanfic about Percy and Travis might have had a really unique take on their characters that just didn't resonate with the majority of the fandom at the time. For example, if it deviated too much from the established personalities of Percy and Travis in the original books. Another possibility is that the writing style was difficult to follow. Sometimes, fanfic authors get a bit too experimental and it can turn readers off.
Well, there could be many reasons why a fanfic about Percy Jackson and Travis Stoll has been forgotten. Maybe it was written a long time ago and got buried under newer and more popular fanfics. Or perhaps the author didn't promote it well. It could also be that the plot wasn't as engaging as others in the Percy Jackson fandom.