Site-to-site VPN connection randomly dropping the VPC connections to AWS

We have recently upgrade our Sophos UTM hardware and imported the same configurations from the previous one.

After a week we upgrade it to firmware version 9.503-4 and couple of days later , we started to having VPC connection dropping from sophos side.

We have checked the connection logs from AWS and it says AWS detected Peer dead.

Does anyone came across the same situation? if so what will be the solution for this.

I will be able to provide IPSEC logs if that helps.

Thanks,