我找到了解决方案.无需更改guzzlehttp/guzzle/src/Client.php，这是另一个问题所建议的.

I found the solution. No need to change guzzlehttp/guzzle/src/Client.php which is suggested in another question.

解决方案:

1. 从 https://curl.haxx.se/下载cacert.pem文件docs/caextract.html
   将cacert.pem放在您喜欢的地方.

1. Download cacert.pem file from https://curl.haxx.se/docs/caextract.html
   Put the cacert.pem somewhere you like.

编辑php.ini

两行:

curl.cainfo=D:/Servers/php/sslfiles/cacert.pem  
openssl.cafile=D:/Servers/php/sslfiles/cacert.pem 

1. 重新启动apache httpd.