as n4no said, on v bulletin, when u use multi tabs, it makes the server think ur trying to DDOS [double denial of services] which means, flooding the server capacity making it unable to function properly, or not function at all. so when many people do this, they get the proxy error or page cannot be found etc.Also, it happened once earlier , few weeks back, to most of the sythe members, that was because sythe was actually DDOSd, so next time this happens, a possible explanation could be, many people have opened multi tabs, or sythe has been DDOSd. this is temporary tough