@FXBS Thanks for reaching out to Microsoft Q&A, apologize for any inconvenience caused on this.
Based on the shared information, I have looked at the backend logs I can see that yours is free trial subscription.
Free trial subscription has set of limitations and has limited access as well. I would suggest you re-try the webapp creation operation in another region and let us know if you are facing the issue.
Refer to this documentation, for more information about subscription limits.
Feel free to reach back to me if you have any further questions on this.