Hi,
From the screen shots and the configuration, I could find 2 issues.
1. You are using aggressive modeon both the sides, please change it to main mode for the phase 1 IKE negotiation.
policy ikephase1policy_VPN1 {
mode aggressive; <<<<<<<<<<<<<<this should be main mode on both the sides
proposals ikephase1proposal_VPN1;
pre-shared-key ascii-text "Password"; ## SECRET-DATA
2. The tunnel interface defined in the IPSEC VPN section is also not correct.
vpn ike-vpn-VPN1 {
bind-interface st8.0; <<<<<<<<<<<<<<<not correct tunnel interface, it should be st0.* and not st8.0.
ike {
gateway gw-VPN1;
ipsec-policy ipsecphase2policy_VPN1;
Please configure the above things and also do let us know if the st0 interface is assigned toa security zone or not.
Regards,
Guru Prasad