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Email sending errors in Uku: causes and solutions

What to do if emails are not being sent? How to identify failed emails and how to resend them, either one by one or in bulk.

Maria Müürsepp avatar
Written by Maria Müürsepp
Updated this week

Troubleshooting Email Notifications and Delivery Issues

Sometimes, emails may fail to send from Uku. This can happen for several reasons. Common issues with Google and Microsoft accounts include: Additionally, problems with automated email triggers or temporary authentication errors in linked accounts can also result in email-sending failures. Issues may also arise when exceeding the email sending limits defined by providers like Microsoft. In such cases, Uku automatically redirects emails through its secure mail server to ensure their delivery.

  • expired integration token,

  • expired or changed email password,

  • a typo in the email address.

  • incorrect or outdated email settings,

  • email account limitations or quotas.

  • exceeding email service provider send limits.

When Uku cannot send an email, a notification appears in the Uku notification center. Uku provides an automatic re-routing mechanism for emails exceeding send limits, which ensures reliable delivery even in cases of temporary provider-imposed restrictions.

Missing Emails and Spam Filtering Issues

Emails may sometimes fail to reach the intended recipient's inbox due to spam filters or other email client restrictions. Popular email services like Outlook might mark legitimate emails as Spam or redirect them to the Junk folder. To troubleshoot this issue in Outlook, check not only your Spam or Junk folders for misplaced emails but also review any filtering or quarantine rules in your email settings. You can also add Uku’s sending domain to your whitelist to prevent future issues.

Recipient-Side Solutions for Missing Uku Emails in Outlook

If Uku invitation, password reset, or other automated emails are not appearing in Outlook, follow these troubleshooting steps to resolve the issue.Steps to Resolve Missing Emails

  • Ask the recipient to review their Spam or Junk folders for the email.

  • If found, mark the email as "Not Spam" or move it to the main inbox to train their email client to recognize future messages from Uku as safe.- Review your email settings to ensure Uku emails are not restricted by filters, and add Uku's domain to the whitelist for uninterrupted delivery.

Preventative Tips for Stable Email Delivery

To avoid email delivery issues:

  1. Monitor email send volumes and adhere to email provider-imposed caps.

  2. Encourage recipients to add your email address to their safe sender list.

  3. Validate email client settings periodically to ensure legitimate emails are not flagged as spam.4. Whitelist Uku’s domain in your email server or client settings to preemptively allow emails from Uku.

You can resend failed emails in two ways:

  • one by one

  • in bulk

How to resend emails one by one

  1. Click on the error notification under Uku notifications. You’ll be redirected to the task where the email failed.

2. The task will show an error message, and clicking on it will display the reason for the failure.

  1. Fix the issue (e.g., update the integration or correct the password). If reconnecting, ensure the email account is properly configured with updated login credentials and recheck its functionality.

4. Then go to the client card – the quickest way is to click the star icon next to the client’s name.

5. On the client card, open the "Communication" tab.

Scroll down to see a list of failed emails.

Click "Resend" next to the email you want to send again.

How to resend all failed emails at once

  1. Go to the client card and select "Email Outbox",

    or
    go to Settings > Emails > "Tools" tab,
    then click "Outbox for emails".

2. In the opened view, use the filter bar to apply the correct filters:

  • select the appropriate date range,

  • company,

  • email status (e.g. Error),

  • optionally choose a specific client.

Email status options:

  • Warning – shown only for failed emails related to Client Portal messages. If these cannot be sent via integration, they are redirected to uku@getuku.com.

  • Sent – emails that were successfully sent.

  • Error – emails that failed to send (e.g., due to an expired integration or changed password that requires an update).

3. After applying the filters, click the refresh icon on the right.

4. Fix the issues that caused the errors.

5. Select the emails you want to resend.


⚠️ Only emails with "Error" status and related to automated sending can be resent this way.

6. Click "Send failed emails", confirm your selection, and then click "Send all."

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