my server works but then not working?

[val3nt1no]

well i fixed all my ports i been trying to do this for 4 to 3 days now and still cant get it to work. this is what happens, i tell my freinds to connect to the ip. they all join and we play and i look on master server list. and its not there. and its weird it saids people joined but then 1 min later it saids they left and for about 10 mins the server is on the list then it disappers when i load up the SRCDS but my freinds don't dissconnect the other people dissconnect while joining the master server list while its up for 10 mins and then it disappers

if anyone can help me please do

P.S sorry for my bad engilsh