diff --git a/infra/main.bicep b/infra/main.bicep
index eae09eacb..33af6fb38 100644
--- a/infra/main.bicep
+++ b/infra/main.bicep
@@ -223,8 +223,8 @@ var allTags = union(
   },
   tags
 )
-@description('Optional created by user name')
-param createdBy string = empty(deployer().userPrincipalName) ? '' : split(deployer().userPrincipalName, '@')[0] 
+@description('Tag, Created by user name')
+param createdBy string = contains(deployer(), 'userPrincipalName')? split(deployer().userPrincipalName, '@')[0]: deployer().objectId
 
 resource resourceGroupTags 'Microsoft.Resources/tags@2021-04-01' = {
   name: 'default'
diff --git a/infra/main_custom.bicep b/infra/main_custom.bicep
index dfb8f7711..c84319d70 100644
--- a/infra/main_custom.bicep
+++ b/infra/main_custom.bicep
@@ -223,8 +223,8 @@ var allTags = union(
   },
   tags
 )
-@description('Optional created by user name')
-param createdBy string = empty(deployer().userPrincipalName) ? '' : split(deployer().userPrincipalName, '@')[0] 
+@description('Tag, Created by user name')
+param createdBy string = contains(deployer(), 'userPrincipalName')? split(deployer().userPrincipalName, '@')[0]: deployer().objectId
 
 resource resourceGroupTags 'Microsoft.Resources/tags@2021-04-01' = {
   name: 'default'