错误:使用Boto python时,"请求中包含的安全令牌无效"

当我在nginx上运行我的django项目时,我收到此错误.我使用dynamodb作为数据库,S3使用S3来提供项目中的静态文件.在localhost上运行时,该项目运行正常.

该项目最初是在另一个ec2实例中托管的,它运行起来就像魅力一样.我从该实例的图像中启动了一个新的ec2实例.而现在它正在抛出这个错误.事情是,

当我在命令行上运行一些测试代码时,连接正常.

但是在项目运行时会抛出此错误.

JSONResponseError: 400 Bad Request
{u'message': u'The security token included in the request is invalid.', u'__type': u'com.amazon.coral.service#UnrecognizedClientException'}
Request Method: POST
Request URL:    http://ec2-54-200-144-115.us-west-2.compute.amazonaws.com/?attempt=1&code=AQBfOzPR4Hlgrpkjz-qXQj8b7OLq6cm1NM_oZf64Wz3EmlX2-VDS6qfZ5V5f0Tmbx4MrLc4SGuJxUHa8drQClz3A1IWMVqUGKLEEW_0ol1RqClI8cZViWreBm5c3HJ-Vp48Xx81a7gvXSjRNJUn-kazXqahDrgsAeLez_8FrXIb_HWHyekhnUmxgkskRGBNzcTtpqASNe3agzG3ZZowCMYi6bDBAdVuODli3ApWQWENSmjLaN5QbZWbGo3ATvJNMAUQjj6VTHCkVS-UWcuh-PtwAAFtUqb8HkLsbFG31KevwPKz6x10ojD45pe03zA1SF_g
Django Version: 1.5
Exception Type: JSONResponseError
Exception Value:    
JSONResponseError: 400 Bad Request
{u'message': u'The security token included in the request is invalid.', u'__type': u'com.amazon.coral.service#UnrecognizedClientException'}
Exception Location: /srv/www/test/local/lib/python2.7/site-packages/boto/dynamodb2/layer1.py in _retry_handler, line 1530
Python Executable:  /srv/www/test/bin/python
Python Version: 2.7.3

无法理解发生了什么.谁能帮我？