Fix Zoho Mail Delivery Delays: MFA Solutions

How can I fix email delivery delays in Zoho Mail, particularly for MFA and OTP codes?

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Zoho Trusted Partner in Digital Transformation

Zoho Mail Email Delivery Delays: Causes, Analysis, and Proven Fixes for MFA & OTP Issues

Struggling with time-sensitive emails like MFA codes or verification OTPs arriving late in Zoho Mail? You're not alone—delays of 15 minutes to hours can disrupt authentication workflows and business operations. In this comprehensive guide, we'll break down the root causes, provide step-by-step troubleshooting, and offer actionable solutions to ensure reliable delivery. Whether you're on a free plan or enterprise tier, these strategies will help you optimize Zoho Mail for faster, more dependable email performance.

Why Zoho Mail Emails Are Delayed: Key Causes

Understanding the problem is the first step to fixing it. Zoho Mail's robust anti-spam measures and infrastructure queuing often lead to delays, especially for transactional emails like MFA codes from services such as Google, AWS, or Microsoft. Based on official Zoho documentation and user reports, here are the primary culprits:

  • Greylisting: Zoho's default anti-spam feature temporarily rejects emails from unfamiliar senders, prompting retries after 15-60 minutes. This is a common issue for first-time MFA senders.
  • Spam Filtering and Whitelisting Gaps: Emails from untrusted domains may get caught in spam checks, even if basic filters are off.
  • Queue Overload on Free Plans: Shared queues on free or Lite plans (5-10GB storage) can cause backlogs, while Premium plans (50GB+) offer priority processing.
  • Authentication Checks (SPF/DKIM/DMARC): Strict verification can add processing time if sender records aren't perfectly aligned.
  • Storage and Quota Limits: Accounts near 80% capacity may trigger throttling, delaying incoming messages.
  • Routing Issues: Suboptimal MX records or data center congestion can extend delivery times.

Recent updates in 2026 confirm greylisting remains active by default, but paid plans like Zoho Workplace provide SLAs for 99.9% delivery uptime. For more on Zoho Mail plans, check the official pricing page.

Immediate Solutions: Quick Fixes for Zoho Mail Delays

1. Whitelist MFA Sender Domains in Zoho Mail

Bypassing spam checks for trusted authentication services can eliminate greylisting delays. Zoho prioritizes whitelisted domains for faster routing.

  • Log into Zoho Mail Admin Console > Control Panel > Anti-Spam > Whitelist.
  • Add common MFA domains: *@amazonses.com, *@sendgrid.net, *@mailgun.org, *@postmarkapp.com, *@accounts.google.com, *@login.microsoft.com, *@okta.com, and *@auth0.com.
  • For inbox rules: Settings > Filters > Create New Filter > Condition: From contains domain > Action: Never send to Spam and Mark as Important.
  • Add senders to Contacts for extra priority.

Pro Tip: Test with a sample MFA request from Google. Delivery should improve within minutes. Learn more in our Zoho Mail FAQ guide.

Source: Zoho Anti-Spam Documentation

2. Check and Optimize Storage Quotas

Full inboxes slow processing. Zoho recommends staying under 80% capacity to avoid throttling.

  • Go to Settings > Account > Storage Usage.
  • Clear Trash, Spam, and old attachments—aim for under 80%.
  • Enable auto-archive for emails older than 30 days.