I had this problem. Signing in or pressing the "Check for an updated license" link did not work for me. My solution was to restart Visual Studio, try again (sign in and check for license). Restart Visual Studio, try again. I had to do this several times and then it worked! (I also tried pressing the "File" menu that is available for a short period of time before the annoying request window appears again.) Maybe you just don't get connected to the server or the server itself doesn't update its database fast enough.

对于VS2019，我可以用我的github账户注册:

然后它会发送密码到你的电子邮件，你就可以签名了。

登录后，30天的试用期就会消失!

“如果你已经登录了，注销，然后再登录。” -b1nary.atr0phy

VS 17社区版是免费的。你只需要用你的微软账户登录，一切就会恢复正常。

另一个答案，当你有一台机器，你没有互联网连接，不能登录，在这里- https://dimitri.janczak.net/2019/07/13/trial-period-reset-of-visual-studio-community-edition/。

这些文件在github - https://github.com/1Dimitri/VSCELicense/releases/tag/1.0上。

从自述文件:

原有模块使用情况

下载/克隆这个存储库 以管理员身份运行PowerShell.exe 导入模块: 导入模块名称X:\PATH\TO\VSCELicense

用法:

Get Visual Studio Community Edition license expiration date

Get-VSCELicenseExpirationDate -Version VS2019

Set license expiration date to current date + 10 days

Set-VSCELicenseExpirationDate -Version VS2019 -AddDays 10

对我来说，问题实际上是我把机器弄坏了。配置和看起来像VS不能有一个连接 我在machine.config中添加了以下代码行

<!--
<system.net>
 <defaultProxy>
  <proxy autoDetect="false" bypassonlocal="false" proxyaddress="http://127.0.0.1:8888" usesystemdefault="false" />
 </defaultProxy>
</system.net>
<!--
-->

将前一节替换为:

<!--
<system.net>
 <defaultProxy>
  <proxy autoDetect="false" bypassonlocal="false" proxyaddress="http://127.0.0.1:8888" usesystemdefault="false" />
 </defaultProxy>
</system.net>
-->

VS开始工作。