diff --git a/packages/backend/src/models/entities/instance.ts b/packages/backend/src/models/entities/instance.ts
index 83c88e284..3a46f01f5 100644
--- a/packages/backend/src/models/entities/instance.ts
+++ b/packages/backend/src/models/entities/instance.ts
@@ -171,8 +171,9 @@ export class Instance {
 	})
 	public infoUpdatedAt: Date | null;
 
-	@Column("Domains for account ats", {
-		nullable: true,
+	@Column("varchar", {
+		length: 128,
+		comment: "Domain for account ATs",
 	})
 	public accountDomain: string | null;
 }