I have a problem with my server when player logs in because many players dropped in the ground specially at Police Department area. Sometimes dead and sometimes in the tunnel.
Moved to #server-development:server-discussion 
Sounds like YMAPs not loading; do you have any in your PD areas?
Yeah i added a ymap add on at pd
This could be the issue then; if the spawns are static, perhaps move them out of the YMAP area?
Or i will stop the ymap?
Download [RELEASE] v2: Fix holes in the map (up to After Hours)
and start the resource. should fix or reduce these occurrences
Hello i am using this since i started my server
how many ymaps do you have running? and how many resources are they all using?
5-10 ymaps I think .
and how many resources is your server running at the moment?
because i think the issue is, is that for whatever reason, the server isn’t loading the chunks in game before your players are there. i mean falling through the map sometimes does happen. it happens on every server. but if its happening a lot for you and the rest of your players then its definitely something server side rather than a player simply not having a good enough PC