Email Issues and Troubleshooting


Types of Errors

There are two types of errors that you will see when attempting to send emails:

  • Dialog box - this takes the form of an error dialog that appears after a email has attempted to send. These indicate that the connection with the server was not successfully established.

  • Status error - these show up against each email which could not be sent in the Email Wizard in the form of a red 'Status' indicator. Click the box to determine the error that occurred. If an email in the list appears with a green status indicator, this indicates the email was sent successfully, even if others in the list are marked red. The error code and message are produced by the mail server in this case. The message is provided by the email server and thus messages will vary depending on the SMTP server that is being connected to, even for the same error.

When you encounter a Status Error, VETtrak does have the ability to display a more detailed breakdown of the steps your mailserver took when attempting to send the email. This is located in the bottom-right hand side of the wizard, and can be expanded like so:

These details should explain where the process failed, and if you need to send this information to VETtrak Support for troubleshooting you can press the Copy button and paste it into a VETtrak support email.

Hosted Customers

If you are hosted with VETtrak, please note that the firewall in our hosted environment only permits email to be sent out of standard SMTP ports (25, 465, and 587).

If your mail server is on a non-standard port, please send an email to requesting that your mail server be unblocked, indicating the hostname and port number for your mail server.

We will only accept unblock requests which specify the mail server hostname in the request. We will not unblock a port to allow connection to all mail servers, apart from the aforementioned standard SMTP ports.

Troubleshooting Email Errors

Below is a list of email errors that can occur when attempting to send email in VETtrak. These take the form of a code and a message. For server connection problems, you'll get a 5 digit code and a dialog box, for SMTP errors, you'll get a red 'Status' indicator and a 3 digit error code (and possibly a sub-error code after this).

The 'Message' column is an indication only and the actual error returned for a given code will depend on the SMTP server software in use. If your error matches a code, even if the message is slightly different, it is most likely caused by the same issue as listed in the 'Explanation/resolution' column for that code.

10013Access deniedVETtrak has been blocked from opening the connection to the mail server. Try disabling any firewall/anti-virus software as this commonly blocks SMTP to prevent viruses mass emailing. If emailing works after having disabled security software, you will likely need to add an exception to allow VETtrak to send emails.
10060Connection timed out

VETtrak was unable to contact the mail server. Check the settings entered in 'File', 'Global preferences', 'Email preferences'. In particular, if you are a hosted customer, ensure you do not have a local address here.

If you are hosted with VETtrak, and are using a non-standard SMTP port, you must contact VETtrak support to request your mail server be unblocked. See Hosted Customers above for more information.

11011Host not foundThe DNS lookup for the mail server failed. Check the settings entered in 'File', 'Global preferences', 'Email preferences'. In particular, if you are a hosted customer, ensure you do not have a local address here.
421 4.3.2Service not availableThis is an error returned by the mail server indicating that it doesn't want to service the request. This could be due to IP filtering, etc. being applied on the mail server. Check if your email server could be blocking emails or if you need to enter different details into 'File', 'Global preferences', 'Email preferences' to send mail successfully.
530 5.5.1 OR 530 5.7.14 similar)This message is typically issued by Gmail indicating that authentication failed. If you are certain the details are correct, they may need to enable less secure apps in their Gmail settings. See Cloud Service Email Settings for more information about configuring VETtrak for Gmail.
535 5.7.3Authentication unsuccessfulThis indicates the authentication settings are not correct. Check the settings entered in 'File', 'Global preferences', 'Email preferences'. If 'Use individual staff member email logins' is ticked, go into the Client Wizard for the affected staff member and ask them to verify the details listed against 'Email username' and 'Email password'.
550 5.7.1Unable to relayThe user does not have permission to send emails to an external domain. This is usually caused by missing user credentials in 'File', 'Global preferences', 'Email preferences'.
276Server certificate verification failed. Connection Aborted.

This error indicates that the certificate received from the mail server isn't valid. This often indicates one of the following:

  • The hostname that has been entered in the 'Mail server address' field in VETtrak doesn't match the one on the certificate
  • The certificate has expired
  • The certificate is a self-signed certificate - VETtrak only accepts certificates signed by a trusted certificate authority

To check the certificate being sent by the mail server, you can use the "Check TLS" service at - enter the hostname as entered in the Email Preferences in VETtrak (if you use a different port from 587, also click 'FULL version' and enter the port in the 'MX Port' field). This will show the certificate given to VETtrak when connecting. If a verification error results (e.g. due to a self-signed certificate), then VETtrak will not work either.

Note that TLS can often be disabled by setting the SSL/TLS option to 'None (no SSL)' and setting the port to 25 to use non secure SMTP, however this is not recommended.

161: SMTP protocol error. 451 5.7.3STARTTLS is required to send mailThis indicates that the SSL/TLS Connection Method and/or the Authentication Type are not configured correctly.

These are configured within File -> Global Preferences -> Email Preferences. Refer to our Cloud Service Email Settings article and for further details on the recommended settings, and request your IT Team to provide any other details required to meet your organisation's needs.
 161: SMTP protocol error. 554 5.2.0 'Submission.Exception:SendAsDenied'

This indicates that someone has attempted to reference an email address that is different to the configured 'Send As' email account in the preferences.

Essentially unless the mail server has been configured in a specific way, you can't Send as one user, and then try and specify a Reply Address as someone else.

Commonly this is fixed by using Individual Staff Member Log Ins or making sure the Reply To address is the same as the Sender email address.

161: SMTP protocol errorService unavailable, Client host [] blocked using Spamhaus.This indicates the authentication settings may be missing within VETtrak. Check the settings entered in 'File', 'Global preferences', 'Email preferences'. You will need to ensure the SSL/TLS connection method is 'Explicit', and change the Auth type to username/password and enter a valid email address and password that is accepted by your email server.
161: SMTP protocol error. 534 5.7.14Username and Password not acceptedThis usually indicates that you may be unable to email through Gmail. If comfortable, test enabling “Access for less secure apps” (which just means the client/app doesn’t use OAuth 2.0 - for the account you are trying to access. It's found in the account settings on the Security tab -> Account permissions.
535-5.7.14Follow on Error

This is usually a follow on from the above error ^

Go to and click Continue.

Then you can authenticate your Additional Email Address from your Gmail Account.

552 5.2.3 Guidelines. y3-20020a17090a134300b0022bb9f05753sm6843806pjf.48 - gsmtp.This indicates the file being sent exceeds a file size limit of 25MB while using Google as an SMTP provider. The file will need to be reduced in size, or in the case of a report, reduced volume of Data Entry to resolve the issue.
See Gmail SMTP errors and codes for more information.

535 5.7.8

Bad CredentialsThis indicates that two factor authentication has been enabled on your gmail account and as such, an application specific password will need to be set up in order for emailing to work through VETtrak. The following article steps you through the process of creating this within your google/G suite account. Those details can then be entered within your email preferences in the password field.
Sign in with app passwords - Google Account Help

535 5.7.139

Authentication unsuccessful, the request did not meet the criteria to be authenticated successfully. Contact your administrator.This means that two factor authentication has been enabled on your Office365 account, this does not work with SMTP based communication and as such, an SMTP relay will need to be configured within your Office365 tenant in order to work with VETtrak. This Microsoft article explains how to set up an SMTP relay (option 3 preferred), your mail server admin will also need to set up an SPF record containing our server IP in order for the relay to work properly.



The SMTP Server requires a secure connection or the client was not authenticated. The server response was 5.7.57 Client not authenticated to send mail. Error 535 5.7.139 Authentication unsuccessful SMTPClientAuthentication is disabled for the tenant.This is the same as the above although it refers to the Office365 tenant as a whole, the error means that basic authentication has been disabled and SMTP authentication will no longer work. As above, an SMTP relay will need to be set up by following the steps in the Microsoft article. An SPF record will also need to be set up in order for the relay to work.

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