crypto isakmp key <MY_KEY or MY-KEY>
I struggled for a while trying to bring up a dmvpn tunnel -- with IPSEC.
I kept receiving this error. Cisco says it is a catch-all error.
%CRYPTO-4-IKMP_BAD_MESSAGE: IKE message from 169.254.60.6 failed its sanity check or is malformed
Finally I found that my KEY was bad. I used a hyphen "-" and it would not come up. When I changed it to an underscore "_", it came right up.
A lot of wasted time troubleshooting the config so many times, and it turned out to be just a bad key. No warning comes up saying not to use a hyphen. Maybe I am spoiled by warning messages. ;-)