OL98: Invalid Response Error Received When Retrieving Mail

This Error occure when The Post Office Protocol (POP) server has sent either a blank or invalid reply to the client request for a Unique Identifier Listing (UIDL).

You are attempting to retrieve Internet e-mail when you receive the error message:
The POP3 server sent an invalid response. please contact your system administrator. Server response '6' (Account '' POP3 Server: '' Error Number: 0x800ccc93)
The entry, , contains your information as provided by your Internet service provider (ISP). The entry, , is the friendly name you created for the mail account.

RESOLUTION

The error condition in most cases refers to a single message. There are three methods to clear the message.

Method 1

Use another mail client to download the message.

Method 2

Use the telnet terminal client to delete the message from the POP server. For more information about using telnet, please see the following article in the Microsoft Knowledge Base:
187782 OL98: How to Use Telnet to Test an Internet Mail Connection and Outlook Support

Method 3

If the option to keep messages on the server is selected, temporarily change this option to clear the message. To change this option, follow these steps:
1. On the Tools menu, click Accounts.
2. Click the Advanced tab. Under Delivery, click "Leave a copy of messages on the server."
3. Click OK and then Close.

MORE INFORMATION

Internet mail standards are defined in a series of documents that are known as Requests For Comments (RFC). The standards for POP mail transport were initially defined in RFC 1725. Changes to the standards are published in RFC 1939 which supercedes RFC 1725.

RFC 1939 specifies that a POP server assign unique identifiers to messages. Previously these identifiers were optional. RFC 1939 also specifies the following parameters for the UIDL:

• The UIDL consist of the message number followed by a space and then the arbitrary server-assigned number from one to 70 characters in the range, 0x21 through 0x7E.

• The UIDL remain persistent across multiple sessions.

• A UIDL should never be reused by the server for as long as a entity exists.