Environment variable not being passed to sam deploy

Question

I'm using sam deploy to deploy 2 dynamoDB tables. But I keep getting errors relating to the fact it cannot resolve [Environment] such as:

Error: Failed to create changeset for the stack: <STACKNAME>, ex: Waiter ChangeSetCreateComplete failed: Waiter encountered a terminal failure state: For expression "Status" we matched expected path: "FAILED" Status: FAILED. Reason: Template format error: Unresolved resource dependencies [Environment] in the Resources block of the template

The sam template is:

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: <Description>

Resources:

  Database:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub "${Environment}-Membership_Database"
      AttributeDefinitions:
        - AttributeName: "id"
          AttributeType: "S"
        - AttributeName: "membershipNumber"
          AttributeType: "N"
      KeySchema:
        - AttributeName: "id"
          KeyType: "HASH"
        - AttributeName: "membershipNumber"
          KeyType: "RANGE"
      BillingMode: "PAY_PER_REQUEST"

  MemberHistoryTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub "${Environment}-Membership_History"
      AttributeDefinitions:
        - AttributeName: "id"
          AttributeType: "S"
        - AttributeName: "time"
          AttributeType: "S"
      KeySchema:
        - AttributeName: "id"
          KeyType: "HASH"
        - AttributeName: "time"
          KeyType: "RANGE"
      BillingMode: "PAY_PER_REQUEST"
      TimeToLiveSpecification:
        AttributeName: "ttl"
        Enabled: true

Outputs:

  MembershipDatabaseTableName:
    Description: "Table name of the membership database"
    Value: !Ref Database
    Export:
      Name: !Sub "${AWS::StackId}-MembershipDatabaseTableName"

And by samconfig.toml looks like this: (I want to export several environment variables, but am concerned that this file is the issue).

version = 0.1

[staging.deploy.parameters]
stack_name = "Stack-Staging"
s3_prefix = "StackStaging"
region = "eu-west-2"
confirm_changeset = false
resolve_s3 = true
capabilities = ["CAPABILITY_IAM","CAPABILITY_AUTO_EXPAND"]
image_repositories = []
parameter_overrides=[
  "Environment=staging",
  "AdultsStripePaymentLink=https://buy.stripe.com/...",
  "JuniorsStripePaymentLink=https://buy.stripe.com/...",
]

To run the deployment I'm running:

sam build
sam deploy --config-env staging

What am I doing wrong? Thank you in advance!