Information about Yahoo Error 999

When trying to access a Yahoo service (i.e. Yahoo Mail, Yahoo Groups, Yahoo News, Yahoo Search or Siteexplorer), you receive the following error message:

Unable to process request at this time — error 999 Unfortunately, we are unable to process your request at this time. We apologize for the inconvenience. Please try again later.

Operating System: Any.

Background: This error appears to be a “catch-all” error code that Yahoo serves up when it doesn’t have a more specific error code. It essentially means “Oops! Something went wrong but we don’t know what, so we’ll just say that Error 999 occurred.”

The most common reason for receiving Yahoo Error 999 is due to some sort of bandwidth limiting system that Yahoo has put in place on their servers. Once you have exceeded your allotted bandwidth for a specific period of time Yahoo gives you this Error 999 message and doesn’t allow you to access the service. People have primarily reported receiving this error when they try to access Yahoo Mail or Yahoo Groups, but other Yahoo services may also be affected.

Why has Yahoo done this? There are two reasons that I can think of:

1. To prevent DoS (Denial of Service) attacks.
2. To stop automated tasks from hammering their servers with hundreds of requests a second.

There are many programs around that offer to automate access to various Yahoo services, i.e. check your Yahoo mailbox every 5 minutes, archive Yahoo Groups messages, download files from the Yahoo Groups Photos and Files sections, etc. If you use one of these automated tools then there is a very real possibility that you will run into the Error 999 message. Normal human usage of the Yahoo services shouldn’t normally generate enough traffic to trigger the Error 999 message unless you’re a very heavy user.

It appears that Yahoo uses your IP address to track the amount of traffic you’re generating on Yahoo, and once you reach the limit you get blocked by the Unable to process request at this time — error 999 message. Once triggered you will find that your IP address has been blocked for a period of time, somewhere between 2 and 24 hours usually.