TiDB版本 v4.0.0
DM版本：1.0.5
主库网络中断，导致DM同步出现如下异常。主库连接恢复后，通过resume-task 命令也无法恢复DM同步。
请问如何可以恢复DM同步？
"Type": "UnknownError",
"msg": "[code=30012:class=relay-unit:scope=upstream:level=high] start reader for UUID .000001: start sync from position (master-bin.000022, 246980536): dial tcp 192.168.1.121:3306: connect: no route to host\
github.com/pingcap/dm/pkg/terror.(*Error).Delegate\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/pkg/terror/terror.go:267\
github.com/pingcap/dm/pkg/binlog/reader.(*TCPReader).StartSyncByPos\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/pkg/binlog/reader/tcp.go:79\
github.com/pingcap/dm/relay/reader.(*reader).setUpReaderByPos\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/reader/reader.go:166\
github.com/pingcap/dm/relay/reader.(*reader).Start\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/reader/reader.go:111\
github.com/pingcap/dm/relay.(*Relay).setUpReader\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:610\
github.com/pingcap/dm/relay.(*Relay).process\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:304\
github.com/pingcap/dm/relay.(*Relay).Process\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:191\
github.com/pingcap/dm/dm/worker.(*realRelayHolder).run\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/relay.go:167\
github.com/pingcap/dm/dm/worker.(*realRelayHolder).Start.func1\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/relay.go:143\
runtime.goexit\
\t/usr/local/go/src/runtime/asm_amd64.s:1357",
"error": null
}