System.Net.WebException: The remote name could not be resolved:

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I am testing an endpoint that I am experiencing some issues with.

I am simply using HttpClient in a loop that performs a request each hour.

var httpClient = new HttpClient();
var message = httpClient.GetAsync(url).Result;
Console.WriteLine(message.StatusCode);

Once in a while I am getting this exception:

System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The remote name could not be resolved: 'xxx'

The experience is that right after the exception, the URL can be accessed. In a browser you simply refresh the page and all is good.

I still haven't got any reports from users experiencing it so I am wondering if it's just a local issue here but could use a little information to help diagnose.

Is there a way to check if The remote name could not be resolved is caused by an DNS issue or by a web server issue from the exceptions? Can I get more information out of HttpCLient or do I need more advanced diagnostic tools?


It's probably caused by a local network connectivity issue (but also a DNS error is possible). Unfortunately HResult is generic, however you can determine the exact issue catching HttpRequestException and then inspecting InnerException: if it's a WebException then you can check the WebException.Status property, for example WebExceptionStatus.NameResolutionFailure should indicate a DNS resolution problem.


It may happen, there isn't much you can do.

What I'd suggest to always wrap that (network related) code in a loop with a try/catch block (as also suggested here for other fallible operations). Handle known exceptions, wait a little (say 1000 msec) and try again (for say 3 times). Only if failed all times then you can quit/report an error to your users. Very raw example like this:

private const int NumberOfRetries = 3;
private const int DelayOnRetry = 1000;

public static async Task<HttpResponseMessage> GetFromUrlAsync(string url) {
    using (var client = new HttpClient()) {
        for (int i=1; i <= NumberOfRetries; ++i) {
            try {
                return await client.GetAsync(url); 
            }
            catch (Exception e) when (i < NumberOfRetries) {
                await Task.Delay(DelayOnRetry);
            }
        }
    }
}

System.Net.WebException: The remote name could not be resolved , It's probably caused by a local network connectivity issue (but also a DNS error is possible). Unfortunately HResult is generic, however you can  This web exception is telling you the there was an issue with the "Name Resolution". What it doesn't tell you is that the "name" it's referring to is the "EndpointRegion", for example: USEast1, USEast2 etc.


I had a similar issue when trying to access a service (old ASMX service). The call would work when accessing via an IP however when calling with an alias I would get the remote name could not be resolved.

Added the following to the config and it resolved the issue:

<system.net>
    <defaultProxy enabled="true">
    </defaultProxy>
</system.net>

WebException , the remote name could not be resolved, WebException , the remote name could not be resolved fine. but if i use web service from a remote PC, i got this exception. <system.net>. it throws the error: "System.Net.WebException remote name could not be resolved 'http'". Please note that even if I use 'https' protocol, in the exception it says "remote name could not be resolved 'http'" is it something related to the networks settings on the requested server or something that I can handle while making the request?


Open the hosts file located at : **C:\windows\system32\drivers\etc**.

Hosts file is for what?

Add the following at end of this file :

YourServerIP YourDNS

Example:

198.168.1.1 maps.google.com

WebException: The remote name could not be resolved: 'https', Check if you have to use a proxy server to access external URLs. In that case, add the following to web.config: <system.net>. <defaultProxy>. The remote name could not be resolved: 'sandbox.api.mastercard.com' Hot Network Questions Generating all 2x2 matrices with entries from 0 to 3 whose det is 1 with mod 2 arithmetic


The remote name could not be resolved, Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Net. I had a similar issue when trying to access a service (old ASMX service). The call would work when accessing via an IP however when calling with an alias I would get the remote name could not be resolved.


Web exception: The remote name could not be resolved, If that does not resolve the issue, you might next try flushing the DNS cache on your system: In windows search for cmd, and when the cmd.exe program appears,  If it is having issues resolving the server name, then that is likely a DNS issue on the server. CS simply goes to the connect to the given hostname, and the system will automatically try to resolve the hostname into an IP using the DNS servers the server is configured to use.


Fixing DNS Errors: Remote name could not be resolved – BinTube , "Remote name could not be resolved" errors usually mean that the DNS Follow the instructions for your operating system or router below. setup URL (http://​www.routerlogin.net, http://192.168.0.1 orhttp://192.168.1.1) into a  System.Net.WebException: The remote name could not be resolved: 'na7-api.salesforce.com'. We are not using a proxy or anti-virus on this server. We do have a firewall but it seems that if this were the reason it would not be intermittent. Thanks