Line Trace - Checking ground hits - C++

I’m having a ton of issues with line tracing, and have read up on documentation but am still coming up short.

Essentially, I am looking to “place” items in my world. An object is created hovering above the ground, and I’m trying to cast a line from here vertically downwards - hoping to hit any object with the “PlaceSurface” type. This is important, as I don’t want to be able to place objects on other players for example, and it constrains my gameplay in the way I would like.

The following is the code I’m using to create the trace:

FHitResult HitResult(ForceInit);
FCollisionQueryParams TraceParams = FCollisionQueryParams(FName(TEXT("PlaceVerticalTrace")), true);
GetWorld()->DebugDrawTraceTag = FName(TEXT("PlaceVerticalTrace"));

TraceParams.AddIgnoredActor(GetOwner()); // The player pawn
TraceParams.AddIgnoredActor(PlacingActor); // The object I'm placing

// Cast from placing actor to floor
// This is just the placing actor's position with 2 offsets
FVector TraceStart = FVector(DirectionVector.X, DirectionVector.Y, 100.f);
FVector TraceEnd = FVector(DirectionVector.X, DirectionVector.Y,  -10000.f);

// I'm using a LineTraceSingleByProfile here, but I've also tried by channel, by object - both to no avail.
bool bIsHit = GetWorld()->LineTraceSingleByProfile(HitResult, TraceStart, TraceEnd, FName("PlaceSurface"), TraceParams);

if (bIsHit)
{
	DrawDebugSphere(GetWorld(), HitResult.Location, 2.f, 8, FColor::Green, false, -1, 0, 1);
}

The blue line here shows the debug trace result, it is being cast where I expect, but the floor is not being hit. Here are some screenshots of the collision settings on my floor:

And finally the profile itself:

I would appreciate any thoughts, questions, comments to help my understanding here! Thanks.

So I actually had an “Overlap Box” - which was set to be ignored by this trace. The overlap box however overlapped my entire room. It seems as though when the overlap box was ignored, this also ignored everything that overlapped with it - disabling the overlap box did in fact make my line tracing work as expected.

Many thanks to KaosSpectrum in the Unreal Slackers Discord for helping me get there!