UnityWebRequest 'Unable to complete SSL connection' even with http

Unity Engine
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1

Hi,

I have been getting intermittent issues with the error ‘Unable to complete SSL connection’ using UnityWebRequest and communicating with a local ASPnet server. The network functionality does work with both https and http, and we use custom certificate handling during development. This is on Unity 6000.1.16f1.

I have not encountered this error only until I am sending a large number of requests from one unity client for general load-testing. The error doesn’t occur until the number of requests sent by the instance of unity editor reaches a certain threshold, and then from that point they all failed with response code 0 - Unable to complete SSL connection.

Restarting the unity editor fixes this problem. I have also noticed that changing build profiles (which are pretty much identical) can also fix the issue.

IEnumerator GetGroupData(Action callback, RequestInfo requestInfo = null)
    {
        string getUrl = baseUrl + "/" + groupName; // URL to retrieve the group
        if (requestInfo != null) requestInfo.url = getUrl;
        UnityWebRequest getRequest = UnityWebRequest.Get(getUrl);
        getRequest.timeout = 60;
        getRequest.certificateHandler = new CertificateHand(); // this is a custom certificate handler

        // Send the GET request and wait for the response
        yield return getRequest.SendWebRequest();

        //rest of execution....
}

public class CertificateHand : CertificateHandler
{
    protected override bool ValidateCertificate(byte[] certificateData)
    {
        return true;
    }
}

This may require changes to the server rather than unity code, but I am only getting the issue with Unity and other API tools like Postman are working fine. I am confused why SSL is even being considered with a http request also.

Thank you

2

This doesn’t make sense to me either. Maybe server is configured to redirect requesting to change protocol to https?

3

are you seeing anything in the webserver logs when it fails?

4

This may be the case, I am using Visual Studio to host which has a https endpoint primarily, and then a http endpoint also. When I set up the same server code on an IIS Server as purely http, this works flawlessly.