Can't delete Network Interfaces

Question

Hi!  
  
On our AWS account we're trying to remove an old VPC and its resources, since they're no longer needed. Most of the resources have been created through a Cloudformation template which stack we've tried deleting.  
  
However, we're having issues with removing two of the private subnets, since it appears that their network interfaces cannot be removed. These two subnets have been attached to NAT Gateways with Elastic IP's, which were deleted successfully when we tried to delete the Cloudformation stack.  
  
When we try to detach the Network Interfaces through the console we get the following errors:  
_eni-082ec70af05740ef1: You are not allowed to manage 'ela-attach' attachments._  
_eni-05fe36cf3605dac0b: You are not allowed to manage 'ela-attach' attachments._  
  
Since all of the other resources besides the VPC, its default resources (e.g. default security group) and the aforemented subnets should have been removed by now I'm a bit unsure why the network interfaces can't be deleted.  
  
Affected Network interfaces:  
* eni-082ec70af05740ef1  
* eni-05fe36cf3605dac0b  
  
Affected Subnet IDs:  
* subnet-13d35d5b  
* subnet-4f45bc15  
  
Can you guys see why this issue occurs?  
  
Best Regards,  
Benjamin Simonsson

Answer

Please see https://aws.amazon.com/premiumsupport/knowledge-center/lambda-eni-find-delete/. There are links to some scripts you can run to confirm/identify if the ENIs are owned/held by Lambda.

Answer

After direct discussions with the AWS Technical Support I managed to fix this.  
  
**In case anyone else ever stumbles upon this thread while having the same issue:**  
Our problem was that some of our Lambda functions had old inactive versions that still referenced the subnets which we wanted to delete; this caused their network interfaces to apparently still be in use.  
  
To fix this I went through the relevant Lambda functions in the AWS Console and manually deleted the old versions which were affected. After that the subnets could successfully be deleted.

Answer

Hi again,  
  
We're still experiencing this issue. We'd gladly appreciate some help with solving this.  
  
Best Regards,  
Benjamin Simonsson

Answer

* Warm Greetings Everyone!*
I am having a similar situation with my account . I am unable to delete my Network Firewall , Network Interface, VPC, Endpoints . When trying to delete Network Firewall, this is the error received :
1 * For Firewall *: " **Cannot DeleteFirewall because at least one of the firewall endpoints are missing the AWSNetworkFirewallManaged:true tag: [vpce-00957b459fe0dec1b**] " I have added tags to endpoints per recommendation but still.
2 *For endpoints*: **"vpce-00957b459fe0dec1b - Operation is not allowed for requester-managed VPC endpoints for the service com.amazonaws.vpce.us-east-2.vpce-svc-0f427de517c75a430.**"
3 * Network Interface*: "**Network interface is currently in use by ela-attach-xxxxxxxxxxxx**"

* Kindly note that i have released all elastic IPs, NAT, Internet Gateway.
I need your assistance please because the bill for *Network interface* keeps increasing for a service i don't use.

Can't delete Network Interfaces

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