为什么xml格式正确了，验证的四个字符串都不为null,并且token验证通过，微信依然显示服务出现故障
signature =8fc24d6cbd6d0259c7a9853c7dd802ff028d601dtimestamp =1536909649nonce =1963936087echostr =3320173141099012607
<xml>
<ToUserName>oQkbK5mqzs-7oTt854Ne5xs-4png</ToUserName>
<FromUserName>gh_81289040759e</FromUserName>
<CreateTime>1536909682012</CreateTime>
<Msgtype>text</Msgtype>
<Content>您发送的消息是：123</Content>
<MsgId>6600976885953081817</MsgId>
</xml>
