When you cannot log back in at the spot you logged out at this might have several reasons.
1.) You were carrying something. The liftable you carried will drop in the exact same spot you were standing when logging out, thus preventing you from spawning there again.
2.) You were sitting in a chair, a wagon or a boat (the last two seem to be a bit unclear. I usually was able to log back in on boats, but I have confirmed reports of people who were not. Might be because of a small shift in the location of the boat while logging out or something). Same explanation as above.
3.) You are on private property, that is a village claim or a private claim you have not full permission to be on. The game will not let you log back in because you would need criminal acts to be turned on to walk on said land.