What do I do when the
message "NO_PROPOSAL_CHOSEN" is displayed during debugging?
This problem occurs because no matching security proposal is available.
In phase 1, check whether an IKE proposal matches that of the peer end. In
phase 2, check whether the parameters of the applied IPSec policies, protocols
of referenced IPSec proposals, encryption algorithms, and authentication
algorithms are matched on the interfaces of the two negotiating devices.