The error "unable to verify the first certificate" typically occurs when the SSL/TLS certificate of the server you are trying to connect to cannot be verified. It could be due to various reasons, such as an invalid or expired certificate, a misconfiguration on the server, or network connectivity issues.

Here are a few steps you can take to troubleshoot this issue:

1. Check the server's SSL certificate: Ensure that the server's SSL certificate is valid and properly configured. You can use online SSL certificate checkers to verify its validity.

2. Update your system's trusted certificate authorities (CAs): Sometimes, the root certificates used to verify SSL/TLS certificates might be outdated or missing on your system. Make sure your system has the latest CA certificates installed.

3. Verify network connectivity: Ensure there are no network issues that might prevent your application from connecting to the server. Try accessing the server from a different network or machine to see if the issue persists.

4. Disable strict SSL/TLS checking (not recommended for production): If you are working in a development environment and trust the server, you can temporarily disable the strict SSL/TLS checking. However, this is not recommended for production environments as it can expose your application to security risks.

If none of these steps resolve the issue, it would be helpful to provide more details about your specific code, the server you are trying to connect to, and any other relevant information.

在 Node.js 中使用 fetch 调用 HTTPS API 时出现 "Error: unable to verify the first certificate" 错误，可以按照以下步骤解决：

1. 更新 CA 证书：确保你的系统已安装最新的 CA 证书。你可以通过更新操作系统或手动下载最新的 CA 证书来实现。

2. 添加自定义根证书：如果服务器的 SSL 证书是由自定义根证书签发的，你需要将该根证书添加到 Node.js 的信任列表中。你可以使用 tls 模块的 createSecureContext 方法创建一个包含自定义根证书的安全上下文，并将其传递给 fetch 请求的 agent 选项。

   const https = require('https');
   const fetch = require('node-fetch');
   
   // 自定义根证书路径
   const caFilePath = '/path/to/custom/root/certificate.pem';
   
   // 创建包含自定义根证书的安全上下文
   const secureContext = https.createSecureContext({
     ca: fs.readFileSync(caFilePath),
   });
   
   // 使用自定义安全上下文发送请求
   const response = await fetch('https://api.example.com', {
     agent: new https.Agent({
       secureContext,
     }),
   });
   
   const data = await response.json();
   console.log(data);
   

3. 忽略证书验证（不推荐）：如果你仅在开发环境中遇到这个问题，并且相信服务器的证书是有效的，你可以选择忽略证书验证。但是，在正式环境中不推荐这样做，因为它会导致安全风险。

   process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
   

请注意，忽略证书验证可能会导致你的应用程序受到中间人攻击和其他安全威胁。因此，建议在生产环境中避免使用此方法。

如果以上方法仍然无法解决问题，请提供更多关于你的代码和服务器配置的详细信息，以便我们能够更具体地帮助你解决问题。

在 Next.js 服务端使用 fetch 调用 HTTPS API 时，遇到 "Error: unable to verify the first certificate" 错误，你可以尝试以下解决方法：

1. 添加自定义根证书：如果服务器的 SSL 证书是由自定义根证书签发的，你需要将该根证书添加到 Node.js 的信任列表中。你可以使用 tls 模块的 createSecureContext 方法创建一个包含自定义根证书的安全上下文，并将其传递给 fetch 请求的 agent 选项。

   import https from 'https';
   import fetch from 'node-fetch';
   import fs from 'fs';
   
   // 自定义根证书路径
   const caFilePath = '/path/to/custom/root/certificate.pem';
   
   // 创建包含自定义根证书的安全上下文
   const secureContext = https.createSecureContext({
     ca: fs.readFileSync(caFilePath),
   });
   
   // 使用自定义安全上下文发送请求
   const response = await fetch('https://api.example.com', {
     agent: new https.Agent({
       secureContext,
     }),
   });
   
   const data = await response.json();
   console.log(data);
   

2. 忽略证书验证（不推荐）：与前面提到的一样，在开发环境中可以选择忽略证书验证。但是，在正式环境中不推荐这样做，因为它会导致安全风险。

   process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
   

请注意，在 Next.js 服务端中，你需要将上述代码放在服务器端的适当位置，例如处理路由的请求处理函数中。

如果以上方法仍然无法解决问题，请提供更多关于你的代码和服务器配置的详细信息，以便我们能够更具体地帮助你解决问题。

I apologize for the confusion. In Next.js, you cannot directly set the NODE_TLS_REJECT_UNAUTHORIZED environment variable in the next.config.js file.

To ignore SSL certificate verification during development, you can use the HTTPS_REJECT_UNAUTHORIZED environment variable. Here's how you can do it:

1. Open your next.config.js file.

2. Add the following code at the top of the file:

module.exports = {
  env: {
    HTTPS_REJECT_UNAUTHORIZED: '0',
  },
  // Rest of your Next.js configuration...
};

3. Save the file and restart your Next.js development server.

Please note that ignoring SSL certificate verification is not recommended in production environments as it can expose your application to security risks. Only use this solution during development when you trust the server you are connecting to.

If you encounter any further issues or have more questions, please let me know.