problems people connecting to my oscam

Hey all I have a oscam server with clients connecting to me via cccam on port 12000 but recently 3 people have not been able to connect to me but they connect to me at different houses it seems that all the users trying to connect are subscribers to virgin media broadband although I have other on virgin connecting fine

I thought that they may be blocking ports on that particular users connection so I setup a mgcamd connection using a different port and they are still unable to connect its very baffling can anyone shed any light on this ?

- - - Updated - - -

oh and another thing I have tried is changing my ip address and they still can not connect

I know the problem is their end its quite evident the thing is what's the problem it's deffo something with Virgin media as a friend also has talk talk Internet his box works through that but not his virgin media Internet

P.s the accounts work fine they don't need testing

- - - Updated - - -

Also another friend who got his box of someone else reporting the same issue so it's not just my server

- - - Updated - - -

I think I have found out what the problem is in the virgin media account holders settings when they login to there account online there is an option for child safe on or off if this is set to on it will not connect to unknown sites so it needs to be set to off and then it will connect I am just waiting for a user to get back to me with confirmation that this works

not many and the problem is now fixed via the above method