Hi Karolina Ziminska,
Thank you for reaching out to Q&A forum.
To address your concerns, we would first need to confirm the type of Azure subscription you are currently utilizing, and the type of email account associated with it (Work/School).
Regarding your Enterprise P2 trial, it's important to note that if your Azure subscription is free, it may not support dynamic groups. Confirm that the user account you're using has the necessary license attributed to it for executing this action.
To assess the status of your license, please verify if the P2 trial is active within your tenant. You can typically find this information in the Azure portal under "Subscriptions" or "Billing."
Additionally, it would be helpful if you could confirm whether the account used to access the Microsoft Enterprise Admin Center is assigned either the Global Administrator or User Administrator role within the tenant.
Thank you.