HTTP / HTTPS outbound requests blocked in EC2 instance

TL;DR TCP traffic was blocked internally, that’s why I couldn’t do the requests at that time

I’m having some troubles trying to make HTTP / HTTPS requests from a EC2 instance on AWS.

The instance public IP is working, and I can connect via SSH.

IT WORKS When I try to ping or nslookup a domain:

[root@my-instance etc]# ping google.com
PING google.com (172.217.15.110) 56(84) bytes of data.

BUT when I try to curl an url I’ve got this:

# curl -v https://google.com
* Rebuilt URL to: https://google.com/
*   Trying 172.217.164.174...
* TCP_NODELAY set
*   Trying 2607:f8b0:4004:803::200e...
* TCP_NODELAY set
* Immediate connect fail for 2607:f8b0:4004:803::200e: Network is unreachable
*   Trying 2607:f8b0:4004:803::200e...
* TCP_NODELAY set
* Immediate connect fail for 2607:f8b0:4004:803::200e: Network is unreachable
*   Trying 2607:f8b0:4004:803::200e...
...

I’ve got other instances associated to the same VPC and with the same outbound settings, this is the only one which blocks the outgoing requests.

Some details about the network:

Instance Security Group Outbound settings:

The Subnet attached is also connected to an Internet Gateway:

And these are the ACL traffic settings (which are the same ACL for other instances)

This instance has an Elastic-IP associated and it’s on a VPC (which other instances are also connected and the outbound traffic is OK),

I’ve tried to attach a new security group (a clone from the original) to that instance.

Does anyone has any ideas what’s happening?