当VM Gateway失去联系，无法使用，直接删除GW，或者在VM Network中删除GW连接，均会出现如下错误提示：
错误(21426)
对配置提供程序 4ee559f1-f479-480c-9458-d14b8b1c1779 执行 Microsoft.SystemCenter.NetworkService::UnregisterGatewayVMSubnet 失败。详细例外: Microsoft.VirtualManager.Utils.CarmineException: 无法将子网信息更新到远程访问服务器。(未针对多租户配置远程访问服务器和主机。请在远程访问服务器中修复问题并重试该操作。)
解决办法：
1.在VirtualManagerDB数据库中执行如下操作：
delete from dbo.tbl_NetMan_NATConnection
delete from dbo.tbl_NetMan_NATRule
delete from [dbo].[tbl_NetMan_VMNetworkGateway]
delete from [dbo].[tbl_NetMan_NetworkGateway]
delete from dbo.tbl_NetMan_NetworkServiceMetadata
delete from dbo.tbl_NetMan_NetworkServiceConnection
delete from dbo.tbl_NetMan_NetworkServiceHostGroups
delete from [dbo].[tbl_NetMan_NetworkService]
2.然后重启VMM服务，VM Network中的GW连接、网络服务中的GW都已经消失