Unable to connect to the remote server System.Net.Sockets.SocketException: An attempt was made to access a socket in a way forbidden by its access permissions

[vivekagrawal1110]

I have ASP.Net Web API, to perform SharePoint operation using SharePoint add-in client context . I have deployed Web API on Azure Web Site.
Generally API works fine but randomly gives exception till that Web Site restarts manually.

System.Net.WebException: Unable to connect to the remote server System.Net.Sockets.SocketException: An attempt was made to access a socket in a way forbidden by its access permissions 20.190.151.68:443 at System-NetSockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketlnternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception) End of inner exception stack trace at System.Net.WebClient.DownloadDatalnternal(Uri address, WebRequest& request) at System.Net.WebClient.DownloadData(Uri address) at System.Net.WebClient.DownloadData(String address) at PnP.Framework.Utilities.TokenHelper GetMetadataDocument(String realm) at PnP.Framework.Utilities.TokenHelper.GetStsUrl(String realm) at PnP.Framework.Utilities.TokenHelper.GetAppOnlyAccessToken(String targetPrincipalName, String targetHost, String targetRealm) at PnRFramework.LJtilities.ACSTokenGenerator.GetToken(lJri siteurl) at PnP.Framework.AuthenticationManager.b_56_0(String site) at PnP.Framework.AuthenticationManager. DisplayClass68_0.b 0(Object sender, WebRequestEventArgs args) at Microsoft.SharePoint.Client.CIientRuntimeContext.OnExecutingWebRequest(WebRequestEventArgs args) at Microsoft.SharePoint.Client.ClientContext.GetWebRequestExecutor() at Microsoft.SharePoint Client ClientContext.GetFormDigestI nfoPrivate() at Microsoft.SharePoint.Client ClientContext.EnsureFormDigest() at Microsoft.SharePoint.Client.ClientContext.ExecuteQuery()

Please help me to fix this issue.

[NikoMix]

Can you please provide some sample code on how you are trying to authenticate?

Please make sure, the sample does not contain any sensitive information.

Based on the StackTrace it seams you cannot retrieve/download the manifest from: https://accounts.accesscontrol.windows.net/metadata/json/1?realm=

I do not represent my company.

[patrikhellgren]

@vivekagrawal1110: What version of PnP.Framework are you using? Versions from 1.5.0 have built-in retry handling on SocketExceptions so if you are using an earlier version and this is an intermittent issue you are seeing maybe it would be helpful to have some retries done.