WHMCS error 500 – How we nailed it

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Have you ever thought why it’s important to install the WHMCS updates?

These security updates always protect WHMCS from cyber attacks.

However, customers may face errors like WHMCS error 500 when upgrading their WHMCS to the latest version.

This can happen due to permission problems or because of bad server configuration.

At 1 onlyhost , we often get requests from our customers to fix WHMCS error 500 as part of our Server Management Services.

Today, we’ll see how our Support Engineers update WHMCS and fix the related error 500.



How we do WHMCS Updates

Usually, WHMCS will automatically notify about updates. And, we can see it from the WHMCS admin panel. It will show up as a sign requiring immediate action on the installation.

1. So, we navigate to Utilities > Update WHMCS 

2. Then, we click Update Now.

3. After that, we follow the on-screen wizard that guide us through the update process and select the proper version. Then we update it.

This process work seamlessly most of the time. But often results in 500 errors too.


How we fixed error 500

From our experience in managing servers, we’ve seen customers facing problems while doing an upgrade WHMCS. Any error in WHMCS need detailed troubleshooting. Let’s take a closer look at how our Support Engineers fix the problems with WHMCS.


1. Permission errors

Recently, one of our customers had a 500 error on his WHMCS panel. When he tried to post a ticket, he was getting Internal Server Error:500.

Then our Support Engineers took the following steps to solve the issue.

1. Firstly, we logged into the server as a root user.

2. For further troubleshooting, we checked the Apache error log to identify the root cause and found the following permission denied entries.

[sun May 17 19:16:31.786671 2019] [cgi:error] [pid 27734] [client IP:1024] AH01215: (13)Permission denied: exec of '/home/user/public_html/index.php' failed: /home/user/public_html/index.php
[sun May 17 19:17:49.369686 2019] [cgi:error] [pid 27636] [client IP:1024] AH01215: (13)Permission denied: exec of '/home/user/public_html/index.php' failed: /home/user/public_html/index.php
[sun May 17 19:19:44.399634 2019] [cgi:error] [pid 27639] [client IP:1024] AH01215: (13)Permission denied: exec of '/home/user/public_html/index.php' failed: /home/user/public_html/index.php

3. So, we had to set up the write permission for Apache user on the install folder.

4. At last, we restarted the Apache service.

That fixed the issue and the customers were able to post tickets successfully.


2. Lack of memory in PHP

Similarly, many customers get WHMCS Internal Server Error:500 because of lack of PHP memory too. In such cases, our Support Engineers solve this issue by increasing the memory_limit to the required value.

In order to increase the memory_limit, we take the following steps.

1. We first identify the current value from WHMCS > Utilities > System > PHP Info.

2. Then, we increase the memory_limit directive in the PHP configuration, followed by a web server restart.

That fixes the memory error and WHMCS works normally.


3. Automatic update failure

Sometimes, the Automatic WHMCS update may not work as we expect. It may cause problems like Internal Server Error:500 after the version upgrading. Therefore, our Support Engineers manually upgrade the WHMCS.

1. We download the latest full release of WHMCS from http://download.whmcs.com/

2. Next, we unzip the contents of the WHMCS zip file.

3. Then we upload the new files to your existing installation folder.

4. After that, we visit the installer page directly through > domain.com/whmcs/install.

5. We agree to the WHMCS End User License Agreement and follow the steps on screen to update the database.

6. After the successful installation, we delete the install folder from the server.

That’s it. We now have an updated WHMCS installation.


[Getting 500 error in WHMCS? We’ll fix it for you.]



In short, it is really critical to keep WHMCS in latest stable version. During the upgrade, to avoid WHMCS error 500 we need to set proper file permissions and memory_limit. Today, we saw how our Support Engineers fixed this error.

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