Issue when trying to delete VPC and Network Interface

I am trying to delete AWS VPC (a non default one). I am getting error that "We could not delete the following VPC (vpc-xxxxxxx (xx.xx.xx.x/16)) Network interface 'eni-xxxxxx' is currently in use. (Service: AmazonEC2; Status Code: 400; Error Code: InvalidParameterValue; Request ID: xxxxxx-dd86-47c8-98cd-xxxxxxxxxxx)".

When I tried deleting the related Network Interface, I got error "eni-xxxxxxx: You do not have permission to access the specified resource."

There are security groups associated with the NI (network interface). There are subnets associated with the NI. There are no EC2 instances - all are terminated. There are no VPC endpoints. There are no RDS db, db security group or subnets.

For EC2 SG (security groups), I am getting permission denied error message while trying to delete (even the non default SG against the non-default VPC. This SG has description of "AWS created security group for d-xxxxxxxxxx directory controllers".

For subnets, I am not able to delete them because they are associated with the above mentioned NI.

Can someone help? I have a free tier account and hence even dont have technical support or neither able to post new thread in aws forums (getting error message - Your account is not ready for posting messages yet. Please try again later). I fear this is because I have a free tier account.

Solution 1:

Check 2 things.

• If you have a VPC Elastic IP Address you created in the VPC you are trying to delete.
• Check if you created a AWS ELB in the VPC.

Delete above two resources if present then you will be able to delete the VPC.

Solution 2:

As @karimtabet said, the VPC I was unable to delete was still assigned to an active RDS instance. after removing this RDS instance, I was able to delete the VPC.

Solution 3:

Check if you have any EFS instances or S3 buckets with versioning turned on or cross-domain replication (this is the one that got me recently).

Solution 4:

I solved this by deleting the active load balancer that was attached to the ENIs. You can check active load balancers on EC2 > Load Balancing > Load Balancers