Hi Daniel Casota,
Thank you for reaching out to us on the Microsoft Q&A forum.
With the recent update to Power Automate, spaces are now allowed in subflow names, as mentioned in the knowledge check as shown in below screenshots:
We’ve also contacted the content author regarding this change, and they’ve confirmed that the module will be updated accordingly in the coming days.
If the information is helpful, please Accept Answer & Upvote so that it would be helpful to other community members.