Lambda cold start is around of 65 second

I just created demo app (with VPC 'cause I want to use it with RDS and ElasticCache) that has one controller which returns html file. When I tried to test my lambda I got scary 65 seconds response. I created an another lambda from scratch and it starts less than second. As I found so slow start is caused by “Jets.once” command in compiled lambda, but I don’t understand why.
Appreciate your help (

Added VPC endpoint to one of subnets (NAT didn’t help, maybe, I did it wrong) and it resolved problem. I don’t know much about VPC so if someone understand how it works, please, let me know😉