SMTP Configuration

What is SMTP?

SMTP (Simple Mail Transfer Protocol) refers to the protocol most servers use to handle Outgoing Email. This standard of Email Transmission allows for external Applications and Services (such as the Mail Clients of Microsoft ‘Outlook’, Apple ‘Mail’ etc) to make requests to a server to send the emails to the target recipient.

Why use SMTP?

The Applications and Services you use to send your Emails would by default need to be sent using their own server, or one likely different to your own. This raises two potential issues:

  1. The Application/ Service attempts to send emails using your Email Address as the “Sender” though without any of the further information to validate this as a legitimate transmission from you. When the recipient server then makes a request to confirm the metadata of the Email (such as where it was sent from, and how it was digitally signed) is correct, the validation fails and the Email sent is considered either a security risk, or simply spam. The recipient server based on this failed validation either organises the Email as spam, or simply refuses to accept it at all and sends back a “bounce message”.
  2. The Application/ Service sends a users Emails through the the same server(s) as all their other users, meaning if a single user misuses the service and has their account flagged on a blacklist, then every user is listed as being on that blacklist. Blacklists provide open information of reported “bad senders” and depending on the recipient server, this either has the email organised as spam, or outright rejected with a “bounce message”.

When you set-up your SMTP information within an Application/ Service, the emails are first sent to your typical sending server to then send the email to the recipient. This offers the following benefits:

  • The two aforementioned issues can be completely bypassed
  • For all intents and purposes emails sent from the Application/ Service look to be legitimately sent by you and will pass the majority of all checks of validity
  • All sent emails will be stored in your “Sent” email folder*
  • Any bounce back messages will be delivered to you and handled as they typically would be by your Mail Service Provider

*This is dependant on the set-up of your mail client. This is not a standard of Simple Mail Transfer Protocol.


What are the fields?

If you are on our new KashFlow service we have permitted you the means to define your SMTP details from:

Settings > SMTP Configuration

Therein we present you with the following fields:

The name that appears as the sender. This is useful if you are using a generic business email such as “contact@yourbusiness.com”, but want to define your emails as coming from “The Finance Department”.

The “reply-to” email address, which is utilised when recipients utilise their Mail Clients default “Reply”, or “Reply All” feature. You would usually enter the same email address here as your normal address, though you could specify something else, useful if you are sending emails from “contact@yourbusiness.com” but would like your recipients to reply to “support@yourbusiness.com”.

Your username for your mail server, this is typically your complete email address.

The password linked with the above username, this is typically the same password you use to sign-in to your mailbox.

Outgoing Server
This is the SMTP server, and is typically separate from your IMAP and/or POP3 server names. Below are the typical SMTP server names for common Mail Service Providers:

Mail Service ProviderSMTP Server Name
BT Internetmail.btinternet.com

The port is where your SMTP server looks to for requests, the most commonly used are 25, 465 and 587 though they could be any other number. Below are the typical SMTP ports for common Mail Service Providers:

Mail Service ProviderPort Number
BT Internet465

The method of authentication between the sender and recipient servers to establish a means to convert the message from being viewable as plain text, typically these are either SSL, TLS, or STARTTLS. Below are the typically expected Encryptions for common Mail Service Providers:

Mail Service ProviderEncryption
BT InternetSSL

Please note, KashFlow does not currently accept the defining of STARTTLS encryption. This can typically be substituted for TLS, though you will need to confirm with your Mail Service Provider if this is possible.

How do I set up SMTP?

  1. Navigate to “Settings” > “SMTP Configuration”
  2. Fill in the fields with the appropriate information
  3. Select “Override KashFlow emails with SMTP configuration below”
  4. “Save” to commit the changes to the KashFlow account
  5. “Test Email” to ensure your settings are correct and work



“I cannot see the SMTP Configuration in Settings”
If you are using the Classic KashFlow application, then you will not have this as an option. New features will only be included on the Current KashFlow application, and this process will not change.

“The SMTP Configuration is greyed out”
If you are in your Trial of KashFlow, you will not be able to utilise the SMTP Configuration.

“The Test Email alerts me that it sent successfully but I do not receive anything.”
These are often hard to truly diagnose from our end, and it is almost always best to refer to your Mail Service Provider to inquire why the relay has failed as they will have logs of the attempt, which should include some description as to why the server refused to relay. However, it is not uncommon for mail servers to reject relaying an email if what you have recorded for the Sender Details “Name” and “Email” do not match those recorded for the server/ mailbox so it may serve you well to ensure these pieces of information are correct.

“I have tried using the above SMTP details and nothing works”
If you are having issue with your SMTP information you will need to contact your Mail Service Provider and ensure the details you are submitting in the KashFlow SMTP Configuration fields are correct. As your server and Mail Service Provider operate beyond KashFlow we are not able to advise as to what SMTP values you should be providing. The above suggestions are only common set-ups and do not necessarily apply to you.

“My Google Account is said to send successfully but I still don’t receive anything”
By default, Google will disallow applications external to the Google family from using its SMTP server, however, you can enable this for your specific account. This is achieved by changing a setting of your security and explained in the Google document here: https://support.google.com/accounts/answer/6010255

“My Google Account keeps failing”
If you have enabled 2-Step-Verification with your Google account, then the normal set-up of SMTP details will not work for you. This is because Google expects you to enter an additional passcode every time you sign-in to your Google account from a new place. However, you can bypass this issue by creating an App Password specific for KashFlow from within your Google account that you can then use in the “Password” field without the need of a passcode. More information on using this feature of Google can be found here:

“A few of my recipients are still not receiving my emails”
No recipient server has to accept an email, and can reject it for any reason– there is no legitimate means around this. However, if you are able to see the sent mail from your “Sent” folder, then you should be receiving the “bounce messages” from the recipient server which will detail why they are not accepting your emails. If you are unsure of where these bounce messages are kept you will need to contact your Mail Service Provider.

“Why does my Mail Service Provider also list IMAP and POP3 settings?”
Incoming Email is typically handled by the IMAP and POP3 protocols, though as the capacity to handle Incoming Mail is not a feature of KashFlow these will not be discussed further in this article.

Temporary Issues

“My recurring Invoices are still being sent with the KashFlow default address”
07/04/2016: We are currently aware of an issue with Invoices created through the “Repeat Invoices” feature and set-up to “Automatically email to customer” being emailed through the default KashFlow Email Server. We are looking into this as a priority and will update this article as soon as the fix is released. Please note if an Invoice is created through “Repeat Invoices” and is sent manually, this issue will not be present.

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