Spam Sleuth in POP3 Proxy Mode also uses port 110 (by default). We recommend that you move Web2POP to 109.
If Web2POP is running, then you can right-click on the Web2POP icon in the tray and choose Options, and then set the "Listen to Port" to 109.
If Web2POP shuts down when you run it, it is because the port it is trying to use (110 by default) is in use by another program. Web2POP will give you a message that says something is using the port and it is unable to initialize.
If Web2POP will not run, then you need to edit (or make) a Web2POP.ini file in the Web2POP program directory. It should have these lines:
[setup]
Port=109