Getting "reason": "RESOURCE:PORTS" when running Jenkins build - amazon-web-services

Question

when I run a Jenkins build, my back-end code is not updating in AWS. There seems to be an error when I try to build the Elastic Beanstalk:
Encountered error starting new ECS task: { "failures": [ { "reason": "RESOURCE:PORTS", "arn": "arn:aws:ecs:eu-west-1:863820595425:container-instance/d6b92955-eb16-4911-b874-683155fcd630" } ], "tasks": [] }
Has anyone encountered this before? The port set up in the dockerrun.aws.json file has not been changed in over a year. If I manually restart Task Definitions this backend will eventually update but I need to see why the Ports issue is happening.
My dockerrrun.aws.json file:
{
"AWSEBDockerrunVersion": 2,
"containerDefinitions": [
{
"name": "customerportal-backend",
"image": "<AWS_ACCOUNT_ID>.dkr.ecr.eu-west-1.amazonaws.com/<ECR_REPO_NAME>:latest",
"essential": true,
"memory": 1024,
"portMappings": [
{
"hostPort": 80,
"containerPort": 3001
}
],
"mountPoints": [
{
"sourceVolume": "store-efs",
"containerPath": "/efs-mount-point"
}
],
"links": [
"clamav-rest"
]
},
{
"name": "clamav-server",
"image": "mkodockx/docker-clamav:latest",
"essential": true,
"memory": 1536
},
{
"name": "clamav-rest",
"image": "lokori/clamav-rest",
"essential": true,
"memory": 1024,
"links": [
"clamav-server:clamav-server"
],
"portMappings": [
{
"hostPort": 3100,
"containerPort": 8080
}
],
"environment" : [
{ "name" : "CLAMD_HOST", "value" : "clamav-server" }
]
}
],
"volumes": [
{
"name" : "store-efs",
"host": {
"sourcePath": "/var/app/efs"
}
}
]
}