The error 'This media is not available right now' can appear in two cases:
I have a free teacher account and my project is unavailable
Free teacher accounts come with a 60-day free trial. Once the trial period is over, you will need to purchase a license to continue sharing your project. Please see this page for more information about the free trial.
If you had a free teacher account with ThingLink before 2022, you will need to purchase a license to continue sharing your projects, too. Unfortunately, ThingLink is no longer able to offer free perpetual accounts. However, you can redeem a discount code to purchase the license at a 50% discount - the discount code will be displayed in your account when you log in.