Which type of mismatch is causing the problem with the IPsec VPN tunnel?

Refer to the exhibit.

Which type of mismatch is causing the problem with the IPsec VPN tunnel?
A . crypto access list
B . Phase 1 policy
C . transform set
D . preshared key

View Answer

Answer: D

Explanation:

IKE Message from X.X.X.X Failed its Sanity Check or is Malformed

This debug error appears if the pre-shared keys on the peers do not match. In order to fix this issue, check the pre-shared keys on both sides.

1d00H:%CRPTO-4-IKMP_BAD_MESSAGE: IKE message from 198.51.100.1 failed its sanity check or is malformed

https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/5409-ipsec-debug-00.html#anc17

Reference: https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/5409-ipsec-debug-00.html#ike