As part of YouTube's long term migration to a more unified live streaming experience, they have removed Stream Now as one of the options. Using the new YouTube Live Control Center, you can create an event that either has a scheduled start, or has no recorded scheduled start, it will just start when you start streaming. This is their overall replacement for Stream Now.
Unfortunately, we here at LiveU need a bit more time to finish work started to support this change in workflow. So, in the interim, we will remove the Stream Now button (it doesn't work as is anyway, so we are only removing something that is confusing our users!) and we will support the full new YouTube workflow in a few weeks.
In the meantime, your alternatives for a YouTube workflow include:
1. Use scheduled events - either created on the Solo portal or created in the YouTube Live Control Center - both of these options still work.
2. Use the Solo destination type of Generic RTMP, to stream to any style YouTube event by copying and pasting the ingress information from the YouTube event to the Generic RTMP designation type. Note this method also works around other YouTube limits such as the need for 1,000 subscribers.
Then, in a few weeks, we will add back the option to start a new YouTube event with no scheduled start time, the new equivalent of Stream Now.