Hello Patrick Grud Kristensen1
Thank you for posting in Microsoft Community.
I understand that you have a query in regard to Microsoft Loop. Let's work together in finding the best answer to this matter.
The pop-up you received is indicating that Loop requires a Microsoft 365 Business Standard, Microsoft 365 Business Premium, Microsoft 365 E3 or Microsoft 365 E5 license to use. At this time, it is not clear if Microsoft will include A3 and A5 licenses for Loop. However, you can check with your Microsoft account representative or visit the Microsoft 365 Insider website for any updates on this matter. If you do not have any of the required licenses, you can consider upgrading your Microsoft 365 subscription to gain access to Loop.
We look forward to your next response.
Regards,
Jason Guer
Microsoft Community Moderator