微信-1004,webview-1004问题排查

webview或者微信会随机出现-1004错误,app webview中具体错误如下：

2017-06-27 18:23:12.135 *****[8041:3557857] Error for WEBVIEW: Error Domain=NSURLErrorDomain Code=-1004 "Could not connect to the server." UserInfo={NSUnderlyingError=0x170249150 {Error Domain=kCFErrorDomainCFNetwork Code=-1004 "Could not connect to the server." UserInfo={NSErrorFailingURLStringKey=http://****/index.html, NSErrorFailingURLKey=http://****/index.html, _kCFStreamErrorCodeKey=51, _kCFStreamErrorDomainKey=1, NSLocalizedDescription=Could not connect to the server.}}, NSErrorFailingURLStringKey=http://****/index.html, NSErrorFailingURLKey=http://****/index.html, _kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=51, NSLocalizedDescription=Could not connect to the server.}

先记着，后续记录详细问题排查过程