[nGen.SoNNy]

Try to remove the "PreloadAnimLib" functions from the callbacks you use when the player connects to your server. I had a lag issue with this function and after some tests i found that this "PreloadAnimLib" it's freezing the client while it's in use.

Also if your server it's a shitty Bugged copycat or something like this it may have some infinite loops.
You can check this topic for more info about your problem: https://sampforum.blast.hk/showthread.php?tid=413146