REST服务端 上传音频没问题上传图片失败 本地上传都是成功的 但是放到服务器就是图片上传失败 环信返回500错误

REST 服务端java 调用上传图片的EasemobFile这个类 easemobFile.uploadFile(file) 这个方法报 
The server connection failed and is being reconnected
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Reconnection is in progress...0
Reconnection is in progress...1
Reconnection is in progress...2
 
 
 
500 Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request. Sorry for the inconvenience.
Please report this message and include the following information to us.
Thank you very much!
http://a1.easemob.com:81/1173170330178156/app/chatfiles
URL:
Server: ops-ali-hk-proxy2
Date: 2017/10/11 12:43:51