diff --git a/src/apps.js b/src/apps.js
index dc2d8095d..2f23cdb55 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -1478,10 +1478,7 @@ async function setMailbox(app, data, auditSource) {
     assert.strictEqual(typeof auditSource, 'object');
 
     const { enable, mailboxDomain } = data;
-    let mailboxName = data.mailboxName;
     assert.strictEqual(typeof enable, 'boolean');
-    assert(mailboxName === null || typeof mailboxName === 'string');
-    assert.strictEqual(typeof mailboxDomain, 'string');
 
     const appId = app.id;
     let error = checkAppState(app, exports.ISTATE_PENDING_RECREATE_CONTAINER);
@@ -1491,6 +1488,7 @@ async function setMailbox(app, data, auditSource) {
 
     await mail.getDomain(mailboxDomain); // check if domain exists
 
+    let mailboxName = data.mailboxName;
     if (mailboxName) {
         error = mail.validateName(mailboxName);
         if (error) throw new BoxError(BoxError.BAD_FIELD, error.message, { field: 'mailboxName' });