This error normally means that you have entered an invalid address on the
IP Address to Bind To entries on the Services page in the VPOP3 settings.
The addresses entered here should be either
<Any> or the IP address of a LAN adapter in the PC running VPOP3.
Alternatively, this can be caused by timing issues related to a DNS lookup. On the
Diagnostics tab in VPOP3, press the
TCP/IP Tuning Options button and tick
Use Synchronous DNS