Alright so it doesn’t look like you’re using navmesh at all so it’s not a pathfinding thing. You checked the collision view mode prior to all this and found nothing.
So let’s start checking outliers.
First back up your map, shift the entire terrain 5000 units in a direction and see if the blocking still occurs. This will determine if it’s a worldwide/spawned issue.
If that doesn’t work and you’re still blocked, we now try to check what it’s colliding with. Turn on your player’s overlap/hit events and print out everything that it collides with.
If it prints the name of something when you hit the blocking location, then you’ll have an answer. If you don’t get anything, the next check is to walk into the blocking location, then hit F8 to detach yourself from the player and look around in the outliner for something yellow and spawned that could have caused it. It could be something that isn’t there in editor if it’s to be spawned after play begins.