Impossible to save pipeline trigger changes in Azure Devops-Bitbucket returned the error 'Forbidden'

I'm working with Azure DevOps to create CI/CD pipeline. The source code is hosted in the Bitbucket server. The problem happened when i want to save changes of the CI/CD pipeline trigger. When i have clicked on the save button, i get the error message:

I have admin permissions and however, i can't save and received the error message above.