Azure Web Application Firewall deploy failed

Hello,

i'm trying to deploy a WAF on my subscription but i'm getting this error:

• Status Conflict
• Provisioning state Failed
  Failed

• { "status": "Failed", "error": { "code": "ResourceDeploymentFailure","message": "The resource operation completed with terminal provisioning state 'Failed'.", "details": [ { "code": "InternalServerError", "message": "An error occurred.", "details": [] } ] } }

previosly the waf got "failed state" alone. Now i deleted it and tried to redeploy(on same vnet, is the only one that i have) and now i had that problem. I have another one in the same subscription and in the same resource group and it works fine.

Thank you