Can't connect to an RDS Instance from Lambda (different account tough)

Hello,

I am trying to connect to an RDS Instance for developpement purpose from a Lambda function used as an Authorizer. But it seems to timeout each time.

I have another database which works fine

Some detailed informations :

About the RDS instance Network Configuration :

• RDS Instance is wide open. I can connect from my computer with Pgadmin.
• Inbound rules of the group security attached to the RDS are correct :
  *PGS TCP 5432 - 0.0.0.0/0
  *PGS TCP 5432 - ::/0
• DNS are OK
• Using default aws VPC.

About the lambda function :

• There is already a database settings configured in the code and it works fine.
• Outbound rules of the scurity group attached to the lambda are OK
  ALL 0.0.0.0/0, ::/0
• Public accessibility : Yes
• Code is OK since i can connect to an another database in my account

One difference tough : the rds instance i am trying to connect is not on the same aws account that i am using but in the same region (west3c). I don't think this is a problem.

I am out of idea.

Edited by: MrJibus on Apr 10, 2020 7:06 AM