I have no idea as to whether this is applicable or not, but I found this after doing a bit of hunting.
Troubleshooting Tips
Verify that you have called your cable service provider and given them the serial number and MAC address of your cable modem.
Source:
http://www1.cisco.com/web/consumer/support/modem_DPC2325.html#~troubleshootingAdditional searching also brought me to
this which sounds like it might be applicable.
In any case, this is a problem/situation with your router/modem and/or ISP, not mIRC.