Problems connecting with other servers

Suddenly I am unable to communicate with users on other servers. This is using standard jabber communication. I do not have a problem with connecting with AIM or MSN. The error that I receive in the error log is:

2006.05.08 14:36:36 [org.jivesoftware.wildfire.net.SocketReader.run(SocketReader

.java:158)] Connection closed before session established

This corresponds to an error in the warn log:

2006.05.08 14:36:36 Error verifying key

java.net.SocketTimeoutException: connect timed out

at java.net.PlainSocketImpl.socketConnect(Native Method)

at java.net.PlainSocketImpl.doConnect(Unknown Source)

at java.net.PlainSocketImpl.connectToAddress(Unknown Source)

at java.net.PlainSocketImpl.connect(Unknown Source)

at java.net.SocksSocketImpl.connect(Unknown Source)

at java.net.Socket.connect(Unknown Source)

at org.jivesoftware.wildfire.server.ServerDialback.verifyKey(ServerDialb

ack.java:518)

at org.jivesoftware.wildfire.server.ServerDialback.validateRemoteDomain(

ServerDialback.java:451)

at org.jivesoftware.wildfire.server.ServerDialback.createIncomingSession

(ServerDialback.java:320)

at org.jivesoftware.wildfire.server.IncomingServerSession.createSession(

IncomingServerSession.java:95)

at org.jivesoftware.wildfire.net.ServerSocketReader.createSession(Server

SocketReader.java:208)

at org.jivesoftware.wildfire.net.SocketReader.createSession(SocketReader

.java:601)

at org.jivesoftware.wildfire.net.SocketReader.run(SocketReader.java:109)

at java.lang.Thread.run(Unknown Source)

What could be causing this problem?

Thanks