Troubleshooting Guide: Errors when Sending Emails

Hitting an error when trying to send an individual or bulk email from Zendesk Sell? Use this help guide to uncover what the error means and what you can do to resolve the issue, so you can get your emails in the hands of prospects and customers. If you're encountering an email error when setting up the email integration, try using this help guide instead!

Jump to more information on the specific error message you see in Sell:


Error Explanations & Solutions

Reference the error message you see in Sell to find out more about what the error means, potential reasons why the error was triggered, and suggested solutions.


Error 001: "Email(s) failed to send"

What Happened: We tried sending your email(s) from Sell but something interfered and caused it to fail.

   What does that mean? What can I do about it?
Possibility #1 The cause is unknown Solution: Try sending an email from your email account (outside of Sell) to see if you're able to successfully send emails. If the issue persists, please contact support.



Error 002: Email(s) failed to send due to your sending limit

What Happened: Every email host (Gmail, Office365, etc.) has defined sending limits that determine how many emails can be sent daily, hourly, and sometimes even per minute. For example, some email servers allow for 500 emails to be sent per day and only 100 emails per hour. Keep in mind that you will only be able to send as many emails from Sell as your email provider's sending limit allows. Click here to see a list of common hosts and their sending limits.

Just to clarify, this error indicates that a sending limit in place on your email account has been exceeded, so your server has blocked any further emails from being sent - this means you won't be able to send anymore emails from your email account nor Sell, until the limit resets.

  • By default we allow you to send up to 300 emails per day from your Sell account, although we're happy to increase this limit if your email server's sending limit allows for more sends per day
  • Please verify your email account sending limits first, then our Support Team will gladly help to increase the number of emails you can send per day from Sell
  • We strongly recommend increasing each user's sending limit in Sell no higher than 1,000 emails per day
   What does that mean? What can I do about it?
Possibility #1 You've sent more emails than what your email host allows. Exceeding your email (per day) sending limit means you won't be able to send anymore emails from your email client or from Sell, until the 24-hour rolling limit resets. Solution: Wait some time then try to send the email again
Possibility #2 You've sent too many emails at one time. Every email host has an email sending "rate limit" that defines how many emails can be sent at one time.
  • For example, if your email host's rate limit allows 200 emails to be sent at once but you try sending a bulk email to 400 prospects, then you'll exceed your email sending (rate) limit.
In some cases, this can cause your email account to be blocked (i.e. you won't be able to send any kind of email for 24+ hours).
Solution: Always check your email host's sending limits to know how many emails you're able to send daily, hourly, or even per minute. You can learn this by:
  1. Try checking your email account settings (outside of Sell)
  2. If you've checked settings with no luck, try doing a quick google search (i.e. "What is [insert email host] email sending limits?")
If you're sending a bulk email, try splitting it up into smaller groups. For example, if you're sending an email to 400 recipients but you can only send 200 emails at once (due to your rate limit), then try splitting it up into a few separate bulk emails
Possibility #3 Your email provider has detected your email behavior as potential spamming. These triggers can differ depending on your provider Solution: Review your email provider's best practices to ensure you aren't performing "unusual activities" (e.g. see Gmail's here). If not, try sending the email again



Error 003: Recipient's email address is not valid

What Happened: We use the email address stored on the Lead or Contact card to send your business emails from Sell. This error indicates that we tried to send your email but the Lead or Contact's email address is not valid.

   What does that mean? What can I do about it?
Possibility #1 There's a typo in the Lead or Contact's email address Solution:
  1. Navigate to the Lead or Contact card
  2. Click 'Edit' (next to Lead/Contact name)
  3. Locate the 'Email' field and review the email address to ensure it's correct:
  • No extra characters
  • No extra spaces
  • No misspellings
  • Only 1 email address is listed in this field
Possibility #2  The person's email address has changed and/or is no longer in use Solution:
  1. Try contacting them by phone to get a valid email address
  2. Try Reach (or your preferred data provider) to uncover this person's valid email address