If you are accessing LinkedIn from multiple devices at the same time, or running different automation tools at the same time, LinkedIn will likely sign you out, which could caused the campaigns to stop.
LinkedIn will trigger and shows Captcha's when it detects unusual use if the user only sent a few connects a day, and now it's sending 100.
A few things to consider doing to avoid this issue:
1 - Make sure that you only login from one device to LinkedIn, where Alfred is installed
2 - Don't allow anyone else with access to your login details
3 - If you login to LinkedIn from multiple devices/locations, don't log out when you leave
4 - Pause Alfred for a few days
5 - Reduce Alfred's operating hours