Site to Site VPN Error

Hi,

i had a site to site vpn connection between 2 sites until yesterday. Suddenly today i stopped working. In fw logs there seem to be no error. On the peer side, the only error is :

"srx240-02a kmd[33482]: IKE Phase-1 Failure: Invalid cookie recvd [spi=^E)?^NM-^@??0, src_ip=<none>, dst_ip=50.208.33.177]"

However, i could not find a solution related to that error message. While everything was working, today even the IKE phase seems to be down ?

I feel desperate, anybody had this issue or any ideas appreciated 

Thanks