Below given are the most probable reason for this error.
1. The Phase 1 proposals do not match.
2. The IP address specified for the (remote) gateway is in correct.
3.The external-interface is in correct.
4 .The dynamic entry specified for the (remote) gateway is incorrect.
From your config I can eliminate the first 3 possibilities . To make sure 4th is not an issue can you add below config and check.
set security ike gateway IKE_Gate remote-identity inet 184.108.40.206
set security ike gateway IKE_Gate remote-identity inet 220.127.116.11
commit the changes and then check the tunnel status.
If this don’t fix, please share the complete kmd logs and "show security ipsec inactive-sa" output