我正在尝试使用sendGrid发送电子邮件（在我的移动应用程序中）。因此，我编写了一个云函数并将其部署到firebase中。（使用此功能，访问https://angularfirebase.com/lessons/angular4-transactional-
email-with-cloud-functions-and-
sendgrid/）。

它已上传到Firebase。但是，当我尝试发送发帖请求（使用postman
{"to":"user1@gmail.com","from":"duser253@gmail.com","subject":"test- email","content":"content"}）时，firebase日志中显示了一些错误

SendGridError: Response error
at /user_code/node_modules/sendgrid/lib/sendgrid.js:104:23
at ClientRequest.<anonymous> (/user_code/node_modules/sendgrid/node_modules/sendgrid-rest/lib/client.js:124:7)
at emitOne (events.js:96:13)
at ClientRequest.emit (events.js:188:7)
at TLSSocket.socketErrorListener (_http_client.js:310:9)
at emitOne (events.js:96:13)
at TLSSocket.emit (events.js:188:7)
at connectErrorNT (net.js:1040:8)
at _combinedTickCallback (internal/process/next_tick.js:80:11)
at process._tickDomainCallback (internal/process/next_tick.js:128:9)
  message: 'Response error',
  response: 
   { statusCode: 500,
     body: 
      { message: 'getaddrinfo ENOTFOUND api.sendgrid.com api.sendgrid.com:443',
        name: 'Error',
        stack: 'Error: getaddrinfo ENOTFOUND api.sendgrid.com api.sendgrid.com:443\n    at errnoException (dns.js:28:10)\n    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:76:26)' },
     headers: {} }