Most of these error codes represent a temporary issue and resolve themselves without troubleshooting.

• 999
• BadCharset
• ClientJSErrorandinvalidactions
• ComposeFailed
• CURLERROR
• FarmNameNotFound
• FolderListFetchFailed
• GetDisplayMessageFailed
• GetMessageFailed
• GetMessageInvalidId
• HTTPERROR
• InputInvalid
• InternalServerError
• InvalidRequest
• ListMessagesFailed
• MailboxOpenFailed
• MaxAttempts
• MessageDeleteFailed
• MessageFetchFailed
• MessageIdsNotFound
• MessageNotFound
• MessageSaveFailed
• MessageSelectionNotFound
• MessageTooLarge
• MetaDataMissingPath
• MoveMessagesInvalidId
• NullResponse
• O3Farm
• ResetSpamFilterFailed
• SaveMessageFailed
• ServerError
• SetMetaData
• SetMetaData
• SetUserDataFailed
• TooManyCallsBatched
• UnknownError
• UserDataFetchFailed
• UserOpenFailed
• UserPreferenceFetchFailed

Usually these are temporary errors that will resolve themselves within 2 hours. If you are receiving one or more of these error codes, please try the following:

1. Click your browsers Refresh button, then retry.

If the error continues, try:

2. Logging out of Yahoo! Mail.
3. Closing all web browsers.

4. Restart a web browser and log into Yahoo! Mail.

If the error continues:

5. Try clearing your internet browser’s Cookies and Cache.