diff --git a/atst/app.py b/atst/app.py
index 04aed44d..1499671c 100644
--- a/atst/app.py
+++ b/atst/app.py
@@ -186,6 +186,7 @@ def map_config(config):
         # with a Beat job once a day)
         "CELERY_RESULT_EXPIRES": 0,
         "CELERY_RESULT_EXTENDED": True,
+        "OFFICE_365_DOMAIN": "onmicrosoft.com",
         "CONTRACT_START_DATE": datetime.strptime(
             config.get("default", "CONTRACT_START_DATE"), "%Y-%m-%d"
         ).date(),
diff --git a/atst/domain/csp/cloud/azure_cloud_provider.py b/atst/domain/csp/cloud/azure_cloud_provider.py
index 7c976b8d..b85bed09 100644
--- a/atst/domain/csp/cloud/azure_cloud_provider.py
+++ b/atst/domain/csp/cloud/azure_cloud_provider.py
@@ -327,9 +327,7 @@ class AzureCloudProvider(CloudProviderInterface):
         if result.status_code == 200:
             result_dict = result.json()
             tenant_id = result_dict.get("tenantId")
-            tenant_admin_username = (
-                f"{payload.user_id}@{payload.domain_name}.onmicrosoft.com"
-            )
+            tenant_admin_username = f"{payload.user_id}@{payload.domain_name}.{self.config.get('OFFICE_365_DOMAIN')}"
             self.update_tenant_creds(
                 tenant_id,
                 KeyVaultCredentials(
diff --git a/atst/domain/csp/cloud/models.py b/atst/domain/csp/cloud/models.py
index 859158a0..27f2c9c7 100644
--- a/atst/domain/csp/cloud/models.py
+++ b/atst/domain/csp/cloud/models.py
@@ -4,6 +4,7 @@ from typing import Dict, List, Optional
 from uuid import uuid4
 import re
 
+from flask import current_app as app
 from pydantic import BaseModel, validator, root_validator
 
 from atst.utils import snake_to_camel
@@ -526,7 +527,7 @@ class UserMixin(BaseModel):
 
     @property
     def user_principal_name(self):
-        return f"{self.mail_nickname}@{self.tenant_host_name}.onmicrosoft.com"
+        return f"{self.mail_nickname}@{self.tenant_host_name}.{app.config.get('OFFICE_365_DOMAIN')}"
 
     @property
     def mail_nickname(self):
diff --git a/atst/jobs.py b/atst/jobs.py
index 0094a6dd..77a8c2f6 100644
--- a/atst/jobs.py
+++ b/atst/jobs.py
@@ -190,7 +190,7 @@ def send_PPOC_email(portfolio_dict):
             "email.portfolio_ready.body",
             {
                 "password_reset_address": app.config.get("AZURE_LOGIN_URL"),
-                "username": f"{user_id}@{domain_name}.onmicrosoft.com",
+                "username": f"{user_id}@{domain_name}.{app.config.get('OFFICE_365_DOMAIN')}",
             },
         ),
     )
diff --git a/tests/domain/cloud/test_models.py b/tests/domain/cloud/test_models.py
index e9951c9d..68bcd351 100644
--- a/tests/domain/cloud/test_models.py
+++ b/tests/domain/cloud/test_models.py
@@ -134,9 +134,12 @@ def test_UserCSPPayload_mail_nickname():
     assert payload.mail_nickname == f"han.solo"
 
 
-def test_UserCSPPayload_user_principal_name():
+def test_UserCSPPayload_user_principal_name(app):
     payload = UserCSPPayload(**user_payload)
-    assert payload.user_principal_name == f"han.solo@rebelalliance.onmicrosoft.com"
+    assert (
+        payload.user_principal_name
+        == f"han.solo@rebelalliance.{app.config.get('OFFICE_365_DOMAIN')}"
+    )
 
 
 def test_UserCSPPayload_password():
@@ -167,11 +170,11 @@ class TestBillingOwnerCSPPayload:
         payload = BillingOwnerCSPPayload(**self.user_payload)
         assert payload.password
 
-    def test_user_principal_name(self):
+    def test_user_principal_name(self, app):
         payload = BillingOwnerCSPPayload(**self.user_payload)
         assert (
             payload.user_principal_name
-            == f"billing_admin@rebelalliance.onmicrosoft.com"
+            == f"billing_admin@rebelalliance.{app.config.get('OFFICE_365_DOMAIN')}"
         )
 
     def test_email(self):
diff --git a/tests/test_jobs.py b/tests/test_jobs.py
index 3edfd769..9df83264 100644
--- a/tests/test_jobs.py
+++ b/tests/test_jobs.py
@@ -135,11 +135,11 @@ def test_create_application_job_is_idempotent(csp):
     csp.create_application.assert_not_called()
 
 
-def test_create_user_job(session, csp):
+def test_create_user_job(session, csp, app):
     portfolio = PortfolioFactory.create(
         csp_data={
             "tenant_id": str(uuid4()),
-            "domain_name": "rebelalliance.onmicrosoft.com",
+            "domain_name": f"rebelalliance.{app.config.get('OFFICE_365_DOMAIN')}",
         }
     )
     application = ApplicationFactory.create(portfolio=portfolio, cloud_id="321")
@@ -328,7 +328,7 @@ def test_send_ppoc_email(monkeypatch, app):
             "email.portfolio_ready.body",
             {
                 "password_reset_address": app.config.get("AZURE_LOGIN_URL"),
-                "username": f"{user_id}@{domain_name}.onmicrosoft.com",
+                "username": f"{user_id}@{domain_name}.{app.config.get('OFFICE_365_DOMAIN')}",
             },
         ),
     )