Third party anti-virus software such as those made by Symantec (Norton), McAfee, et al.
may cause Microsoft Outlook and Outlook Express to time-out or fail upon checking for new
email via POP.
Microsoft Knowledge Base Article – 813518, You Receive Time-Out Error 0x8004210a
or 0x800ccc19 When You View a POP3 E-Mail Account with AntiVirus Software Installed.
Microsoft Knowledge Base Article – 272379,
Internet Mail Account Properties
Are Changed by E-mail Protection in Norton AntiVirus 2000.