Not sure we can help without seeing them, screenshot or file wise.
It is possible something has a value that is too high, also other possibilities, such as overwriting or going over the EOF entry in the pub file.
The EOF signifies the end of file. If you make an entry after it, or delete it entirely (or otherwise missing), this could happen.
Likewise, with NPC's, if they have an invalid value, or have been mis-configured in some way, this can also cause a client disconnection, if the NPC is for example spawned on a map, and they load on to that map.
It's likely classes can do the same if they have one allocated, and spells likewise if they have it / attempt to use it.
If you would like me to look in to it further, I'd have to be able to see your pub files to spot the error. Do you have a lot of entries or is it just a few?
If it's just a few, scan through them one by one and look for something that doesn't seem right!
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Host of a blacklisted server...