409 Conflict: Could not write to local resource web.config due to error Access to the path is denied.

This post is about how to fix the issue with 409 Conflict: Could not write to local resource ‘D:\home\site\wwwroot\web.config’ due to error ‘Access to the path is denied.’ when working with Azure App Service.

Recently while working on an ASP.NET Core Web API project - which is deployed using Azure DevOps to an Azure App service, I faced this issue. For some testing purposes I had to modify the web.config file in the wwwroot folder. I tried to do it via Kudu Console. I updated the config, but when I tried to save, I got the error message like this.

Kudu Error

I thought it was because I am trying to save a file which is getting deployed by the DevOps. I checked the pipelines and it was not running. Then I restarted the app service. After some time I realized there is an App Service configuration - which makes the app service as readonly.

Azure App Service Configuration

You can fix this either removing the configuration entry or setting the value to 0 from 1.

Once you make the change and app service updated, you can again open Kudu and update the web.config.

Happy Programming :)