Im having some problems connecting

[iGenerator]

Every time I click on any server I get this:
[spoiler]Connecting to smp.opticraft.net, 25565
java.io.IOException: Server returned HTTP response code: 504 for URL: http://session.minecraft.net/game/joinserver.jsp?user=iGenerator&sessionId=-4368466932747775028&serverId=391d5f62630bc7f7
   at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
   at java.net.URL.openStream(Unknown Source)
   at adl.a(SourceFile:508)
   at jf.a(SourceFile:29)
   at lg.b(SourceFile:273)
   at adl.b(SourceFile:90)
   at ajy.a(SourceFile:45)
   at net.minecraft.client.Minecraft.k(SourceFile:1384)
   at net.minecraft.client.Minecraft.x(SourceFile:719)
   at net.minecraft.client.Minecraft.run(SourceFile:671)
   at java.lang.Thread.run(Unknown Source)
[/spoiler]

EDIT:I tried for the 9th time and I was able to get in, weird.
I have never had a problem with this before if anyone else has had this or knows a fix I would appreciate it.

[Flamefirre!]

  I'm having this problem too... I need help.

[iGenerator]

just keep trying my brother

[Flamefirre!]

   I will be brave...Into unknown internet failures I go!

[Flamefirre!]

OMG back on! WOO!