The output of the show crypto isakmp command shows that the VPN is stuck in MM_WAIT_MSG_6 state. This state means that IKE Phase 1 negotiation is incomplete because the initiator is waiting for the final message from the responder.
A common cause for this issue is a pre-shared key mismatch between the two VPN peers. If the pre-shared key does not match, the peers fail to authenticate each other, preventing the IKE Security Association (SA) from establishing.