WHMCS Gmail SMTP – Quick way to setup

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In today’s business world, sending secure emails plays a significant role.

Likewise, customers consider Gmail as one of the best medium to send emails via WHMCS with sensitive data.

That’s where WHMCS Gmail SMTP feature comes as boon.

However, errors like "SMTP Error: Could not connect to SMTP host" makes trouble while sending emails through Gmail SMTP.

This happens when incorrect password occurs in SMTP settings or due to firewall block and DNS failures

That’s why, at 1 ONLYHOST , we often get requests from our customers to fix WHMCS SMTP errors as part of our Server Management Services.

Today, we’ll see how our Support Engineers set up Gmail SMTP in WHMCS and fix related errors.



Configuring WHMCS to use SMTP

Let’s now check on how we integrate Gmail as SMTP server in WHMCS. This require changes at the Gmail side and WHMCS side.

At the Gmail side, we enable the option to connect from less secure apps. Otherwise, WHMCS connection itself can fail.

Then, we proceed with the settings in WHMCS.

1, Initially, we login to WHMCS admin panel.

2. We navigate to Setup > General Settings > Mail Tab

3. And, we select SMTP as mail type from the drop down list.

4. Then we fill the following fields too.

  1. SMTP Port
  2. Username and password
  4. Hostname

5. At last, we click Save Changes.



How we fixed the common errors

From our experience in managing servers, we’ve seen customers facing problems with Gmail SMTP in WHMCS. Let’s take a closer look at how our Support Engineers fixed these problems.


1. Incorrect password

Recently one of our customers had a problem with sending email through GMAIL in WHMCS. He was getting an error while sending emails. The error said "SMTP Error: Could not connect to SMTP host."

On checking, we could find that the given password was causing the error. He was using the standard password instead of an encrypted password provided by G suite account.

So, our Support Engineers solved the issue by giving the right password in SMTP configuration.

For that, we had to log in to the G Suite account and click on MyAccount. Then selected Sign-In & Security, and under App Passwords, we created a password there and used this password in SMTP configuration of WHMCS.


2. Firewall block

Similarly, another customer came up with a problem after setting up SMTP authentication method in WHMCS. His email was not sending via WHMCS.

Then our Support Engineers found the problem as firewall block. The port 587 was not opened in the firewall configuration file.

Therefore, we had to allow the port in firewall configuration to solve the error.


3. Absence of OpenSSL extension

Sometimes, the emails cannot be sent through SMTP method because of missing OpenSSL extension. The improper installation or it’s misconfiguration causes the problem in sending an email via SMTP in WHMCS.

So, our  Support Engineers check this by looking at the output of phpinfo(). If we find it missing, we install the OpenSSL extension on the server.


4. DNS failures

Again, DNS failures can also cause email errors with WHMCS.

Often customers report errors like “could not resolve host” while sending emails via WHMCS with SMTP. This happens when it won’t be able to obtain the correct IP address to connect to.

Then Our Support Engineers check the working of DNS by using the dig tool​.

dig +short smtp.gmail.com

If there is a mistake in the configuration, we tweak the setting in the DNS settings.


[Having trouble while sending emails via Gmail SMTP in WHMCS? We’ll fix it for you.]



In short, WHMCS Gmail SMTP is an effective method to send email securely. Sometimes errors may happen because of incorrect password in SMTP settings or due to firewall block and DNS failures. Today, we saw how our Support Engineers set up Gmail SMTP in WHMCS and fix related errors.

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