Hello,
Good day to you!
Thank you for reaching out to Microsoft Community!
I can see you've already checked the license settings in the Microsoft 365 Admin Center, and I appreciate your efforts. However, I’d like to kindly ask you to double-check the license assignment once more to ensure that Microsoft Forms is still enabled for your account.
You can fully clear the browser cache, close the browser and then sign into Microsoft 365 Admin Center with your account to do the test again.

If all has been checked, please check whether any Conditional Access policy is set up for your account to block your access to Microsoft Forms in Microsoft Entra ID (Azure AD). For reference: What is Conditional Access in Microsoft Entra ID? - Microsoft Entra ID | Microsoft Learn

Besides that, you also enable Microsoft Forms in Azure by:
- Going to Microsoft Azure > Entra ID > Enterprise Applications.
- You can search for Office Hive or CollabDBService.
- Under Properties, make sure Enabled for users to sign-in is set to Yes

If the issue persists, please provide me more detail:
- Are you the only user experiencing this issue, or are others in your organization seeing the same error?
- Are you using Microsoft 365 through a third-party provider (such as GoDaddy), or is it managed directly by your organization?
- Are you accessing Microsoft Forms through a direct link, or via the Microsoft 365 portal?
- By the way, based on what you mentioned earlier, may I ask if you are an admin for your Microsoft 365 organization?
If my information above is helpful, please mark it as an answer that will help others in the community who have similar questions find solutions to their problems faster.
Please feel free to reply below if you have any update or further concern.
Best Regard,
Tina L - MSFT | Microsoft Community Support Specialist