Can not connect Kong 2.1 to Azure PostgreSQL 9.6 via TLS 1.1 or 1.2

Hi,

I run Kong 2.1 on Ubuntu 18.04 LTS installed on the Azure VM
and I connect it to Azure PostgreSQL (version 9.6).

I create the PostgreSQL server as follows

az postgres server create `
  --resource-group $AzResourceGroup `
  --name $AzPg `
  --admin-user $AzPgUsername `
  --admin-password $AzPgPassword `
  --sku-name GP_Gen5_2 `
  --version 9.6 `
  --ssl-enforcement Enabled `
  --minimal-tls-version TLS1_0 `

and I can connect the Kong instance to the database on this server.

However, if I change the --minimal-tls-version to TLS1_1 or TLS1_2, then the Kong instance can not connect to the PostgreSQL server. By the way, I do set the environment variable KONG_PG_SSL=on
before I run the kong migrations.

AFAIK, PostgreSQL 9.6 does support the newer TLS versions.

Is there an issue with Kong 2.1 or is there any extra configuration necessary?