GameSpy (the licensed technology for query protocols for BF2) has been changing their query protocols for BF2 since the recent patch. Initially they upgraded their protocol to a more secure and DoS protection system.
This morning it appears as if they have reverted back to the older insecure protocol. What does this mean for ServerSpy? Well all Server Monitors and Stats will be effected. We do currently support both protocols, however as gamespy keep switching between the two and its becoming troublesome for us to keep track on what is the current versions.
So if your BF2 server monitor currently appears as down, but you know its up - this will be due to EA/DICE and GameSpy's fickleness to decide on what they plan to do.