经过大约2个月的搜索和阅读，终于有了解决方案.将此内容添加到app.config对我来说是有用的，而无需进行任何代码更改:

After about 2 months of searching and reading finally there is a solution. Adding this to app.config worked for me without the need for any code changes:

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

所以我的app.config现在看起来像这样:

so my app.config looks like this now:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
    </startup>
  <system.net>
    <defaultProxy useDefaultCredentials="true" />
  </system.net>
</configuration>

请为此提供原始答案学分！ https://***.com/a/40900485/7202022

Please give original answer credits for this! https://***.com/a/40900485/7202022