Clients are unable to connect to server during selenium tests Clients are unable to connect to server during selenium tests google-chrome google-chrome

Clients are unable to connect to server during selenium tests


You can usually solve pre-flight errors with a change to your web.config:

<system.webServer>    ...<httpProtocol>    <customHeaders>        <add name="Access-Control-Allow-Origin" value="*" />        <add name="Access-Control-Allow-Headers" value="Origin, X-Requested-With, Content-Type, Accept, Cache-Control" />        <add name="Access-Control-Allow-Credentials" value="true" />        <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS" />    </customHeaders></httpProtocol></system.webServer>

Or via code in a custom handler with something like:

if (request.Headers.Contains("Origin") && request.Method.Method == "OPTIONS"){    var response = new HttpResponseMessage();    response.StatusCode = HttpStatusCode.OK;    response.Headers.Add("Access-Control-Allow-Origin", "*");    response.Headers.Add("Access-Control-Allow-Headers", "Origin, Content-Type, Accept, Authorization");           response.Headers.Add("Access-Control-Allow-Methods", "DELETE, POST, PUT, OPTIONS, GET");}

If it works you can then try refining things by e.g. changing Access-Control-Allow-Origin to just your front-ends address.


Assuming you are using windows OS. If yes then, did you allow your application to bypass windows firewall..? ex: if you have a application running on localhost:9000, then you need to make sure windows firewall has rules to allow port 9000.

Hope, this resolves your issue.