Livestream does not support streaming directly from IP cameras. However, there are a few workarounds for this, all of which will involve capturing your IP camera via a computer's desktop.
One way is to use Livestream Producer's screencapturing feature.
You can also use Livestream Studio to screencapture your IP camera. One way is by using the Remote Camera client to bring a desktop on the same network as your Livestream Studio system in as a remote camera source.
Additionally, if your Livestream Studio system has a second monitor, you can add a local screencapture as an input source by going to Settings > Inputs, then click the plus (+) button and select that second monitor.
Drag your IP camera into that second monitor. If needed, you can crop the source by going to Input Settings, selecting your screen, and clicking 'Crop.' You can drag the edges in to only show a portion of your second monitor.