diff --git a/src/controllers/MailboxBackendController.ts b/src/controllers/MailboxBackendController.ts
index 8dc5826..4d3b035 100644
--- a/src/controllers/MailboxBackendController.ts
+++ b/src/controllers/MailboxBackendController.ts
@@ -100,10 +100,7 @@ export default class MailboxBackendController extends Controller {
     }
 
     protected async postAddDomain(req: Request, res: Response): Promise<void> {
-        const domain = MailDomain.create({
-            name: req.body.name,
-            user_id: req.body.user_id,
-        });
+        const domain = MailDomain.create(req.body);
         await domain.save();
         req.flash('success', `Domain ${domain.name} successfully added with owner ${(await domain.owner.get())?.name}`);
         res.redirectBack();
diff --git a/src/models/MailDomain.ts b/src/models/MailDomain.ts
index 62bfc2e..9dc3c69 100644
--- a/src/models/MailDomain.ts
+++ b/src/models/MailDomain.ts
@@ -6,7 +6,7 @@ import MailIdentity from "./MailIdentity";
 export default class MailDomain extends Model {
     public id?: number = undefined;
     public name?: string = undefined;
-    public user_id?: number = undefined;
+    public user_id?: number | null = undefined;
 
     public readonly owner: OneModelRelation<MailDomain, User> = new OneModelRelation(this, User, {
         localKey: 'user_id',
@@ -22,9 +22,7 @@ export default class MailDomain extends Model {
 
     public updateWithData(data: Pick<this, keyof this> | Record<string, unknown>): void {
         super.updateWithData(data);
-        if (typeof this.user_id !== 'undefined' && this.user_id <= 0) {
-            this.user_id = undefined;
-        }
+        if (this.user_id !== null && this.user_id !== undefined && this.user_id <= 0) this.user_id = null;
     }
 
     protected init(): void {