Hi cristovao192,
Thanks for reaching out to Apple Support Communities. It sounds like you're having an issue with downloaded Apple Fitness+ content. We're happy to provide some information to assist.
According to the guide below, you should be able to access content downloaded. It does mention "Note: The Burn Bar isn’t available during downloaded workouts." However, check out the details here: Download an Apple Fitness+ workout on iPhone or iPad
You can also test removing and re-downloading.
We recommend also ensuring you are signed into the correct Apple ID and that the requirements are met and testing on another device is available. Devices you can use with Apple Fitness+
If the issue continues, reach out to Apple Support directly to further assist.
Contact Apple Support
Cheers!