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ZeptoMail Bounce Rate and Blocked Accounts: What Zoho's Docs Say

··3 min read

Zoho's ZeptoMail guide puts the accepted bounce rate at 2%, and ZeptoMail blocks accounts that keep sending promotional email. Hard bounces are suppressed automatically, which protects the next send but leaves bad addresses in your own database. So find where the bounces come from (a signup form, an old user table, a marketing send that belongs elsewhere), verify those addresses, mark the dead ones undeliverable in your app, and check new addresses at signup.

What Zoho says

From A guide to email bounces on the ZeptoMail site, read 8 November 2026:

  • "The accepted bounce rate is 2%. This means that for every 1,000 messages you send, 20 will be returned to you."
  • Enhanced status codes: "4.X.X indicates a soft bounce. 5.X.X indicates a hard bounce."
  • "ZeptoMail automatically adds all of the emails that hard bounce to the suppression list. You can also manually add the addresses to this list."
  • Some soft bounces "can turn into hard bounces" after repeated attempts.

From the help article Why was my account blocked?, which now opens under the Zoho CPaaS knowledge base, read 8 November 2026:

  • The platform is "a dedicated platform for sending transactional emails, such as OTPs, password resets, and onboarding emails", and doesn't support "bulk, promotional or marketing emails".
  • "If you use Zoho CPaaS consistently to send promotional or marketing emails, our platform will automatically block email sending for your account." It points bulk senders to Zoho Campaigns.

The block article doesn't give a bounce threshold. The 2% figure comes from the bounce guide.

If your account was blocked

  1. Check what you sent. Newsletters, promotions or announcements to a list are the stated reason for automatic blocks. Move those to a marketing platform.
  2. Check the bounces. A spike usually points to one source: a bot attack on a signup form, an imported user table or a new feature mailing old accounts.
  3. Clean that source (below) before asking Zoho to review, and explain what you changed. Our guide to writing an ESP suspension appeal covers what to include.

Cleaning the addresses behind the bounces

  1. Export hard bounces from ZeptoMail's reports and the address table your app sends to.
  2. Dedupe with remove duplicate emails; fix typos with the email typo corrector.
  3. Upload to the verify page for a live SMTP mailbox check. Mark invalid addresses undeliverable in your database so your app stops trying.
  4. Find repeat soft bounces with the repeat soft bounce finder; Zoho notes these can turn into hard bounces.

Stop bad addresses at signup

Transactional mail is only as clean as the form that collects the address. Check each address before it's saved: see the real-time email verification API, block disposable emails at signup and honeypot fields for signup bots. API calls are counted per plan and aren't part of Unlimited.

What checking costs

  • Starter, $9 a month: 2,500 checks.
  • Pro, $39 a month: Unlimited email verification.*
  • Business, $99 a month: the first 300,000 checks a month at full speed, 5 seats.
  • Agency, $249 a month: the first 750,000 checks a month at full speed, 15 seats, client workspaces.

*Pro fair use: the first 100,000 checks a month at full speed, then slower, never cut off. Unlimited covers email verification, not API calls. See pricing. Check your list free: 100 checks with a Google sign-in, no card.

More reading: Zoho Campaigns list import, Postmark bounce rate, SMTP2GO bounce rate, and the email verification API.

Common questions

What bounce rate does ZeptoMail accept?

Zoho's guide to email bounces for ZeptoMail says the accepted bounce rate is 2%, meaning about 20 bounces for every 1,000 messages.

Why was my ZeptoMail account blocked?

The 'Why was my account blocked?' help article says the platform is for transactional email only and that consistently sending promotional or marketing email leads to an automatic block. It points bulk senders to Zoho Campaigns.

Does ZeptoMail suppress hard bounces?

Yes. Zoho's guide says ZeptoMail automatically adds every hard-bounced address to the suppression list, and you can add addresses manually too.

How do I find what's causing ZeptoMail bounces?

Export the hard bounces from ZeptoMail and look for one domain, one signup form or one feature that accounts for most of them, then clean that source.

Check your list before you send

Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.