Nothing has changed on our end but we all of sudden are starting to get errors below for this line. We event added ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; above it and above TwitterClient and still same issue with TweetInvi. The funny thing is this works on my local computer just fine, just not on Windows R2 which it has done for years on multiple servers.

var authenticationRequestToken = await twitterClient.Auth.RequestAuthenticationUrlAsync(redirectURL);

Error

{"ClassName":"System.Net.WebException","Message":"The request was aborted: Could not create SSL/TLS secure channel.","Data":null,"InnerException":null,"HelpURL":null,"StackTraceString":" at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)rn at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)","RemoteStackTraceString":null,"RemoteStackIndex":0,"ExceptionMethod":"8nEndGetResponsenSystem, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089nSystem.Net.HttpWebRequestnSystem.Net.WebResponse EndGetResponse(System.IAsyncResult)","HResult":-2146233079,"Source":"System","WatsonBuckets":null}

Did Twitter or Azure change anything in regards to TLS?