@Abdelrahman Mokhtar I'm glad to see you were able to resolve your issue. Thanks for posting your solution so that others experiencing the same thing can easily reference this. Since the Microsoft Q&A community has a policy that the question author cannot accept their own answer, they can only accept answers by others, I'll repost your solution in case you'd like to Accept the answer.
. Issue:
While performing the Audio Content creation from Azure Speech Studio, you are encountering the error You don't have operation permissions
.
.
Resolution:
You have given the Cognitive Services Speech Contributor
RBAC role and after waiting for 5-6 hours the issue was resolved.
**
Please do not forget to "Accept the answer” and “up-vote” so that this can be beneficial to other community members.