I can log into WHMCS & can access everything I should be able to access, but if i try to click View PDF Invoice, the following error will occur,

Fatal error: Out of memory (allocated 67633152) (tried to allocate 76 bytes) in /home/xxxx/public_html/whmcs/includes/classes/class.tcpdf.php on line 8419

I have already set the allocated Memory limit to 256MB, but the error still occurs. At that time of the error, the process memory is exceeding the allocation I set. I checked log file, and found the following errors:

#2 /home/xxxxx/public_html/client/includes/classes/class.tcpdf.php(8453): TCPDF->Image('/home/xxxxx/...', 20, 25, 75, 17.5816023739, 'PNG', '', '', false, 300, '', false, 8)
#3 /home/xxxxx/public_html/client/includes/classes/class.tcpdf.php(7881): TCPDF->ImagePngAlpha('/home/xxxxx/...', 20, 25, 337, 79, 75, 17.5816023739, 'PNG', '', '', false, 300, '', NULL)

While I was investigating the issue above I also noticed the error condition pictured below:

WHCMS Screenshot

2 Answers 2


Have you checked the log for any more specific error?

First thing I would do is try re-uploading the /includes/tcpdf.php and /includes/tcpdf_unicode.php files from the original WHMCS zip download.


If you have increased the memory limit, make sure it has been applied for the whole account. If it has been increased in php.ini make sure you set the line below in your .htaccess under public_html directory.

SetEnv PHPRC /home/cPanel-user/public_html.

Replace cPanel-user with your actual cPanel username.

Looking at the error it is an issue with PHP memory limit and not CPU OR server's memory.

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