Skip to main content
How to set up custom sender's email (SMTP)
Updated yesterday

👨‍🔧 Developer recommended.

Clustdoc usually takes care of sending all email notifications through the platform. However, you can also send emails to your recipients through your SMTP mail server.

By allowing you to use your own mail provider, Clustdoc enables you to use email addresses in their own domain to get better open rates and fully manage, monitor, and troubleshoot email delivery.

After you set up your custom email addresses and SMTP servers, you'll be able to change the "From" in the email addresses to your custom address for notifications sent to your recipients.

Prerequisite for setting up your SMTP

There are three requirements for the SMTP server:

  1. It must support LOGIN authentication.

  2. It must support TLS 1.0 or higher.

  3. It must use a certificate signed by a public certificate authority (CA).

Setting up your SMTP

To be able to use your own SMTP server:

  1. Login in to your Clustdoc account and go to the Advanced settings section.

  2. Enter your SMTP server Host, Port, Username, and Password in the appropriate fields. (See example below)

  3. Click Save

Capture_d_e_cran_2020-10-30_a__16.20.34.png

Any issues?

Here are some tips to troubleshoot the most frequent issues with SMTP and email deliverability. Remember that using a professional SMTP service can help you solve most issues.

  1. Check again your username and password.

  2. SMTP normally uses port 25, but it may happen to be blocked by your ISP: try switch to port 587 (or port 465 if you’re connecting via SSL).

  3. The SMTP settings are mistaken. Maybe you configured your mail client with a wrong outgoing server name.

  4. Firewall or antivirus issues. Make sure that you have an exception rule for your SMTP service in your firewall, proxy service or antivirus settings.

If you keep running into issues, it’s likely that you have a general issue with your Internet Service Provider (which you should contact immediately).

We made up a list of the most common email providers, in order to help you set up your SMTP configuration more easily.

Gmail SMTP limitations and possible issues


Gmail, although widely used, does come with limitations and issues that are not talked about so often.

So, to avoid any potential pitfalls, we’ll now go over these limitations and issues one by one.

Sending limit – With Gmail SMTP, users have a daily email sending limit, which depends on the Gmail account they use. Exceeding this limit will cause errors or a temporary suspension.

Rate limit – Another limit Gmail SMTP users have to deal with is the limit on how many emails they can send per minute or per hour. Exceeding this limit will block or delay your email sending.

Security – Sending emails through Gmail SMTP will require a secure connection such as SSL or TLS, which you need to configure correctly in the Gmail SMTP settings. Failing to do so will leave your emails and their data vulnerable to interception and tampering.


Google’s security settings also require proper configuration of things such as two-factor authentication to avoid the blocking of email sending.

Two-factors authentication - if your configuration still fails, also deactivate the Gmail 2FA.

Custom domain – For sending emails from a custom domain such as [email protected] with Gmail SMTP, you need to configure the correct DNS settings. Not doing so will cause your emails to fail SPF, DKIM, and DMARC authentication checks and thus be marked as spam or simply rejected.

Want to get more detailled information, please have a look at the following article https://www.gmass.co/blog/gmail-smtp/

Did this answer your question?