Hello hasan_karim 

Microsoft has stopped supporting Fabric trials for newly created tenants (e.g., Microsoft Entra ID or M365 tenants less than 90 days old). This restriction was introduced to mitigate abuse of trial accounts.

2. Tenant Settings:
• The ability to create Fabric items might be disabled in your organization’s tenant settings. This setting must be enabled by a Fabric or Power BI administrator in the Admin Portal.

3. Trial Capacity Limits:
• Each tenant is limited to five Fabric trial capacities. If this limit is reached, new trials cannot be activated unless existing trial capacities are shared or released

If your tenant was created recently (e.g., within 90 days), you may need to wait until it meets the eligibility criteria or use an existing work/school tenant with established usage of Microsoft products

if this is helpful, please accept the solution

Hi hasan_karim 

May I ask if you have resolved this issue? If so, please mark the helpful reply and accept it as the solution. NandanHegde nilendraFabric thanks for your inputs.

you can refer below document and similar threads.
Fabric trial capacity - Microsoft Fabric | Microsoft Learn
Solved: I cant Activate my 60-day free Fabric trial capaci... - Microsoft Fabric Community
Solved: Re: Unable to open microsoft fabric trial account ... - Microsoft Fabric Community
Solved: Fabric platform trial activation problems - Microsoft Fabric Community

This will be helpful for other community members who have similar problems to solve it faster.

Thank you.

Hi hasan_karim 
I wanted to check if you had the opportunity to review the information provided. Please feel free to contact us if you have any further questions. If my response has addressed your query, please accept it as a solution and give a 'Kudos' so other members can easily find it.
Thank you.

Hi hasan_karim 
I hope this information is helpful. Please let me know if you have any further questions or if you'd like to discuss this further. If this answers your question, please Accept it as a solution and give it a 'Kudos' so others can find it easily.
Thank you.

Hi hasan_karim 

Hope everything’s going smoothly on your end. We haven’t heard back from you, so I wanted to check if the issue got sorted  If yes, marking the relevant solution would be awesome for others who might run into the same thing.