Users of many different Yahoo! services such as Yahoo! Mail, Yahoo! Messenger, or Yahoo! Groups may encounter a “Sorry, Unable to process request at this time -- error 999” message when using any of the applicable Yahoo! services. The 999 message is usually displayed in a webpage such as the one shown below but may also present itself as a custom HTTP protocol header in applications where HTML is not displayed.
A classic example of a 999 error is when a user has requested too many Yahoo! accounts within a preset amount of time. The 999 limit is usually triggered when around 15-20 accounts are created within a 24 hour period
The 999 – unable to process request at this time is a self defense mechanism implemented in many Yahoo! services and web servers as a way to prevent abuse. The 999 error is actually defined as an HTTP response code (http://www.w3.org/Pr...2616-sec10.html) with the value of 999 from a Yahoo! web server. The 999 response code is usually accompanied with an HTML body text saying that the service is unavailable but this is not always guaranteed to be the case. The 999 HTTP code is a custom HTTP code specific to Yahoo! web servers and is not recognized by any Internet standards (http://www.w3.org/Pr...16/rfc2616.html). Below is a web page packet capture using Fiddler (http://www.fiddlertool.com/fiddler/) showing a 999 web server response.
As stated above, the 999 error is usually seen when too many accounts are created from a single IP address (http://en.wikipedia....wiki/IP_address) within a 24 hour period. Almost all account creation programs such as YCC Yahoo! Bot Maker (http://ycoderscookbo...o_Bot_Maker.htm) will encounter a 999 error once the abuse quota has been met. Other similar actions such as excessive posting on community message boards, SPAM like behavior in Yahoo! Mail, or too many password attempts for a particular account may also result in a 999 error. Yahoo! is constantly tuning their systems to prevent abuse so the exact list or amount of suspicious behavior is not known and is subject to change at any time.
Some users may inadvertently encounter a 999 error if they are behind a NAT (http://en.wikipedia....ess_Translation) router with many users or behind a proxy server. This is because both NAT routers and proxy servers will only show their (the NAT or proxy device) IP address to the Yahoo! server and the 999 abuse quote may be filled by multiple users behind the router or proxy. Yahoo! is aware of many of the larger web proxy servers on the Internet such as AOL and apparently implements less stringent abuse limits on those servers. 999 errors are still possible on these servers but more abuse, 150 per 24 hours compared to 15 per 24 hours, is permitted.
As an example we will consider is a home user named Bob who uses a small ISP called RipDSL in his hometown. RipDSL uses a web caching proxy (http://en.wikipedia.org/wiki/Web_cache) to speed up their customer’s web surfing which is a common practice in the ISP industry. Before work, Bob fires up his web browser and checks his Yahoo! Mail. The caching proxy receives the request from Bob and then forwards the request to Yahoo! using the RipDSL proxy’s IP address. Within minutes a second user, Jane, also makes a request to Yahoo! which is also intercepted and the request IP is changed to the RipDSL proxy server. User Jim meanwhile has forgot his Yahoo! Mail password and tries to guess it until he finally gets it after 10 attempts. When Bob gets home from work later that afternoon he once again checks his Yahoo! Mail but this time he is greeted with a cryptic 999 error message even though he did nothing to cause it.
There are a few different ways to combat receiving the 999 error message. Listed below is a list of possible remedies and the situation in which it should be used.
Wait 24 hours
For regular users that are not on a time critical task, the easiest solution is to wait until the 999 error expires. This is usually around 24 hours but may be longer (48 hours) or shorter (12 hours) depending on the amount and type of abuse. The duration is controlled entirely by Yahoo! so the only way to see if the ban has been lifted is to retry the service.
Change IP address
If you need access to Yahoo! immediately then change your IP address if possible. Some ISP’s will grant you a new IP if you renew your DHCP (http://compnetworkin...ewipaddrwxp.htm) license or restart your modem. With DSL you can sometimes disconnect and reconnect to get a new IP and dial-up users will almost always get a new IP with each connection. Additionally you can change ISPs all together by using a different network such as your neighbor’s wireless access point or your local coffee shop’s connection.
If you need access immediately and plan on burning through many 999 messages (creating bots) then you need to connect to Yahoo! through a proxy server. Using a proxy works much like changing ISP’s because Yahoo! sees the IP address of the proxy server and not yours. You can purchase proxy accounts from many different providers or you can use one of the many free open proxies found on the Internet. Purchasing proxy access is certainly more reliable than a free proxy because the bandwidth and latency are much better (not to mention they are guaranteed to stick around for more than a day). Finding free open Internet proxies is much more difficult and care should be taken to scan each proxy before use. I have found from personal experience that only about 5% of proxies found on public lists will actually work. You can visit (how to proxy) for more information concerning how to find and use proxies.
Edited by tansqrx, 06 February 2009 - 08:00 AM.