Hello @WendyR423 ,
At this time you can only send to one segment at a time. If you need to send to multiple segments, I'd suggest creating a new list and adding those segments into that new list. Then you can send the email to the new list.
Thank you for your prompt reply. It's very much appreciated.
It's unfortunate to not be able to send a campaign to more than 1 segment and I'm hoping that changes in the future. For now I copied my campaign and sent it to the other segment. I don't want to make another list because I'm keeping all of my industries together within lists.