Email Certificate Not Secure: How to Solve the ‘Not Verified’ Error in Outlook

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We have the answers you need about the causes of your Outlook certificate problems and the antidote to fix them

Life with SSL/TLS certificates on your email server is a lot like the summer in London. It’s all mild and pleasant until an occasional rain shower strikes you out of nowhere. If a Microsoft Outlook error such as

If a Microsoft Outlook error such as:

  • The server you are connected to is using a security certificate that cannot be verified” or
  • “email certificate not secure” or
  • “Outlook certificate not trusted” or
  • “Security certificate could not be verified”

Then we’ve got you covered with a solid umbrella.

In this post, we’ll cover simple steps through which you can get error past email certificate not secure error in Microsoft Outlook and head out to enjoy the lovely weather. But before diving into the solutions for fixing this certificate-not-secure-for-email issue, let’s first have a look at the reasons behind this error.

Causes Behind security certificate error or ‘The Server You Are Connected to Is Using a Security Certificate That Cannot Be Verified’ Error Message

Wrong Hostname: The most common reason behind this error is that you have the wrong hostname configured in Microsoft Outlook. You might have mistakenly typed in the wrong hostname at the time of configuration.

Incorrect Port Numbers: Another obvious yet common reason is that you have the wrong port numbers entered in your mail server or in Outlook. This error might be caused due to this match in port numbers.

Incorrect Date & Time Settings: This might sound too obvious or simple, but having incorrect date and time settings in your computer could be one of the prime reasons behind this unverified certificate error.

Blocked Ports: If some of the SSL ports used by Outlook are blocked, you won’t be able to connect to the email account and it would result in an error practically shouting that your “email certificate is not secure.”

Certificate Name Mismatch: A potential cause behind this error is having different certificate names in Outlook and your email server. Sometimes, ISPs change the names of their servers and this could cause this error.

Outlook Security Certificate Not Valid: This error generally means your Outlook security certificate has expired and is out-of-date. However, the good news is – you can procure a new certificate to keep your emails secure.

Methods to Resolve The ‘Certificate Not Verified’ Error

Method 1: Correct Certificate Name Mismatch

The first thing you should try is checking the name of the certificate in Microsoft Outlook. Here are the steps to check and correct the certificate name:

  1. Click on the View Certificate button in the error dialogue box.
  2. Now, check the name in the Issued to Name section and to ensure that it has the same name as in the email server. If not, change it accordingly.

Method 2: Correct the Name and Ports of Your Domain

Many a time, having a simple name mismatch in the domain name causes Outlook to believe that the certificate isn’t secure. Usually, this happens for one of two reasons — you have a subdomain as your domain, or you have your domain listed instead of the domain of your hosting company (in case of shared web hosting).

Here are the steps to check and correct the name of your domain:

  1. Go to your email server configuration settings.
  2. Now, go to mail settings and find SSL/TLS settings.
  3. Note the domains for incoming server and outgoing server. Also, be sure to note the IMAP, POP3, and SMTP ports listed.
  4. Open Outlook, go to Account Settings and double-click on the email ID that you wish to configure.
  5. You’ll get a Change Account dialogue box. Change the incoming and outgoing domains to the domains you saw in your email configuration settings.
  6. Click on More Settings, click on the Advanced tab and check whether the ports match the ones listed in your email server configuration settings.
  7. Click OK.
  8. Click Next to finish the job and to check whether the error persists or not.

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