Failing pipeline using bicep file with connectionstrings: The parameter properties has an invalid value

I am using bicep with Azure DevOps to deploy to Azure Web Apps.

I'm struggling to get the connectionString format right and I am being met with the following error from the pipeline log: The parameter properties has an invalid value....

Hoping for some guidance and help..

Pipeline log extract :

{
  "code": "DeploymentFailed",
  "target": ".../myproject-webapp-be",
  "message": "At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/arm-deployment-operations for usage details.",
  "details": [
    {
      "code": "BadRequest",
      "target": "/subscriptions/GUID-HERE/resourceGroups/rg-my-project/providers/Microsoft.Web/sites/my-backend/config/connectionstrings",
      "message": {
        "Code": "BadRequest",
        "Message": "The parameter properties has an invalid value.",
        "Target": null,
        "Details": [
          {
            "Message": "The parameter properties has an invalid value."
          },
          {
            "Code": "BadRequest"
          },
          {
            "ErrorEntity": {
              "ExtendedCode": "51008",
              "MessageTemplate": "The parameter {0} has an invalid value.",
              "Parameters": [
                "properties"
              ],
              "Code": "BadRequest",
              "Message": "The parameter properties has an invalid value."
            }
          }
        ],
        "Innererror": null
      }
    }
  ]
}

Here are my relevant bicep files:

main.bicep:

    param locationID string = resourceGroup().id
    param locationName string = resourceGroup().location
    param tags object = {}
    
    @secure()
    param dbConnectionStringMyProject string
    @secure()
    param connectionStringAzureStorage string
    @secure()
    param MyProjectAPIKey string
    
    module asp 'modules/app-service-plan.bicep' = {
      name: 'myproject-asp'
      params: {
        appServicePlanName: 'my-asp'
        locationName: locationName
        tags: tags
      }
    }
    
    module webappbe 'modules/app-service.bicep' = {
      name: 'myproject-webapp-be'
      params: {
        locationID: locationID
        locationName: locationName
        appServicePlanID: asp.outputs.appServicePlanID
        appServiceAppName: 'my-backend'
        tags: tags
        appSettings: [
            {
                name: 'ApiConfiguration:MyProjectAPIKey'
                value: MyProjectAPIKey
            }
        ]
        connectionStrings: {
            'DBConnectionSqlServer': {
                value: dbConnectionStringMyProject
                type: 'SQLAzure'
            }
            'AzureStorage': {
                value: connectionStringAzureStorage
                type: 'Custom'
            }
        }
      }
    }
    
    module webappfe 'modules/app-service.bicep' = {
      name: 'myproject-webapp-fe'
      params: {
        locationID: locationID
        locationName: locationName
        appServicePlanID: asp.outputs.appServicePlanID
        appServiceAppName: 'my-frontend'
        tags: tags
        appSettings: [
            {
                name: 'ApiConfiguration:MyProjectAPIKey'
                value: MyProjectAPIKey
            }
        ]
        connectionStrings: {
            'DBConnectionSqlServer': {
                value: dbConnectionStringMyProject
                type: 'SQLAzure'
            }
        }
      }
      dependsOn: [
        webappbe
      ]
    }

modules/app-service.bicep:

type NameValuePair = {
  name: string
  value: string
}

param locationName string
param locationID string
param appServicePlanID string
param appServiceAppName string
param tags object = {}

param appSettings NameValuePair[] = []
param connectionStrings object = {}

resource webapp 'Microsoft.Web/sites@2023-01-01' = {
  name: appServiceAppName
  location: locationName
  kind: 'windows'
  identity: {
    type: 'SystemAssigned'
  }
  tags: union(
    tags,
    {
      'hidden-related:${locationID}/providers/Microsoft.Web/serverfarms/appServicePlan': 'Resource'
    }
  )
  properties: {
    serverFarmId: appServicePlanID
    httpsOnly: true

    siteConfig: {
      keyVaultReferenceIdentity: 'SystemAssigned'
      publicNetworkAccess: 'Enabled'
      alwaysOn: true
      minTlsVersion: '1.2'
      use32BitWorkerProcess: false
      webSocketsEnabled: true
      vnetRouteAllEnabled: true
      netFrameworkVersion: 'v9.0'
      cors: {
        allowedOrigins: ['*']
      }
    }
  }
}

resource webappsettings 'Microsoft.Web/sites/config@2023-01-01' = {
  name: 'web'
  parent: webapp
  properties: {
    appSettings: appSettings
  }
}

resource webappConnectionStrings 'Microsoft.Web/sites/config@2024-04-01' = {
  name: 'connectionstrings'
  parent: webapp
  properties: {
    connectionStrings: connectionStrings
  }
}

output appServiceHostName string = webapp.properties.defaultHostName

1. connectionStrings should be defined directly inside the properties:

   resource webappConnectionStrings 'Microsoft.Web/sites/config@2024-04-01' = {
     name: 'connectionstrings'
     parent: webapp
     properties: connectionStrings
   }
   

2. Same for appSettings and it should be an object rather than an array:

   resource webappsettings 'Microsoft.Web/sites/config@2024-04-01' = {
     name: 'appsettings'
     parent: webapp
     properties: {
       'ApiConfiguration:MyProjectAPIKey': MyProjectAPIKey
     }
   }