Players timeout from server

I have a gmod darkrp server and we run script enforcer to prevent hacks. but alot of people time out fromt he server while connecting any ideas? its a windows dedicated server. script enforcer kicks quite a few people also but i am pretty sure it is for their mods they have client side.

we are also having trouble with downloading models we have tried the built in commands and ulx none of them work well so we cant force users to download any custom models which is frustrating.

Also if we install phx it crashes the server whenever it is started up.

this was all done on a fresh install of gmod so there should have been no erros in it already.

any help would be great.