For whatever reason your server is NOT listed on ravensoft's masterserver: ServerList [masterjk2.ravensoft.com]
It is however on the jk2mv/ouned masterserver (which the JK2MV client uses beside the raven master, that's why jk2mv clients still see the server): ServerList [master.ouned.de]
I think the ravensoft master was unreachable for me sometime in the last 24 hours. After issues with the raven masterserver some servers tend to not appear until they were completly restarted once (not just a mapchange, but really quit). Maybe you should try that. If that doesn't help check if your server shows up as protocol 0 (zero): Protocol Zero list [masterjk2.ravensoft.com]
The raven master sometimes sorts servers as protocol zero. If it does it usually helps to keep the server offline for 15 - 30 minutes.