1. 确认您的密钥库已正确设置并包含有效的凭证。您可以使用以下代码示例检查密钥库：

AmazonDynamoDBClient client = new AmazonDynamoDBClient(new ProfileCredentialsProvider());

2. 如果您的密钥库需要密码，则使用以下代码示例：

public static void main(String [] args) throws Exception {

// Provide the correct path and password of the keystore file

System.setProperty("javax.net.ssl.trustStore","/path/to/keystore.jks");
System.setProperty("javax.net.ssl.trustStorePassword","password");

3. 确认您的电脑时间与Amazon DynamoDB服务器时间一致。使用以下代码示例来比较时间：

long ourTime = System.currentTimeMillis()/1000L; long awsTime = getAwsTime(); long diff = Math.abs(ourTime - awsTime);

if (diff > 30) { throw new Exception("The difference between the server time and the local time is greater than 30 seconds"); }

private long getAwsTime() throws Exception { URL url = new URL("https://dynamodb.us-west-2.amazonaws.com"); URLConnection conn = url.openConnection(); conn.connect(); return conn.getDate()/1000L; }