Linqpad 9 cannot download nuget package,but 8 can

when in v9 to use nuget , it cannot work .

it show me like: Error downloading 'Nuget Package Name' An error occurred while sending the request . -unable to read data from the transport connection: 远程主机强迫关闭了一个现有的链接.

they cannot use in v9, but can use in v8:

https://api.nuget.org/v3/index.json
https://mirrors.huaweicloud.com/repository/nuget/v3/index.json   --sometimes can in v8
https://nuget.azure.cn/v3/index.json

Answers