Thank you so much for reaching out on this! One thing we do want to make sure of is that you're trying to transfer through the app and not the desktop or mobile site.
Try the following:
1. Open the StubHub app and login
2. Select My Tickets > Tap the order
3. Tap '...' > 'Send ticket' (1)
4. Select All / Some / or 1 ticket to send
5. Choose to send via text message or via email (2)
6. Enter recipient's phone number or email (3 / 4)
Try those steps and if you're still not able to send those tickets, send a private message to myself or any one of the moderators here and we'll look further into that for you.
You did not indicate if you had spring training or regular season tickets. The transfer feature has not been activated yet but will be shortly before the start of the appropriate season - spring training or regular. You are able to sell now for either season.