Could you please check your Permissions for your project by navigating to Pipelines -> Manage security -> Permissions for <your project>
Ensure you have Project Administrator, Build Administrator, or Contributor access to create and manage pipelines. Also, make sure the permission is set to Allow.
Additional References:
https://learn.microsoft.com/en-us/azure/devops/pipelines/policies/permissions?view=azure-devops
Hope this helps!
Please Let me know if you have any queries.
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