WordPress php memory limit stuck at 128M on CloudLinux + LiteSpeed VPS (cannot increase to 512M)

2 days ago 1
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I’m running a WordPress site on a VPS hosted by PRO ISP (CloudLinux8 + cPanel + WHM + LiteSpeed).
After updating WordPress, Divi, PeepSo, and Paid Memberships Pro, activating PMPro started crashing the site with:

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 2097152 bytes) in /wp-content/themes/Divi/includes/builder/class-et-builder-element.php on line 22355

So PHP memory_limit is stuck at 128M, and Divi/PMPro require more.

For the last week I’ve tried every possible way to increase the memory limit to 512M, but WordPress → Tools → Site Health → Info → Server still shows:

PHP memory limit: 128M

Environment

VPS hosting (ProISP)

CloudLinux

cPanel + WHM

LiteSpeed Web Server

PHP 8.1 (alt-php81)

WordPress 6.x

Important detail: The server is running two PHP engines

My server has both PHP engines installed:

cPanel → alt‑php81 (CloudLinux ALT‑PHP)

WHM → ea‑php81 (EasyApache EA‑PHP)

But phpinfo() shows that LiteSpeed is actually using ALT‑PHP, not EA‑PHP LSAPI:

Loaded Configuration File => /opt/alt/php81/etc/php.ini

This means:

All EA‑PHP settings are ignored

All MultiPHP INI Editor changes are ignored

All php.ini changes are ignored

PHP‑FPM cannot be enabled

CloudLinux CageFS forces memory_limit = 128M

I also uninstalled and reinstalled LiteSpeed (and disabled NGINX earlier), but LiteSpeed still loads ALT‑PHP instead of EA‑PHP.

This might be the root cause of the memory limit being stuck.

What I have tried

I attempted to increase memory in every available place:

1. cPanel → Select PHP Version (PHP Selector)

Set memory_limit = 512M

No effect (WordPress still reports 128M)

2. cPanel → MultiPHP INI Editor

Edited domain settings → memory_limit = 512M

No effect

3. cPanel → MultiPHP Manager

PHP-FPM cannot be enabled for this domain (option disabled)

4. WHM → MultiPHP INI Editor

Edited ea-php81 and alt-php81 → memory_limit = 512M

No effect

5. WHM → MultiPHP Manager

PHP-FPM can be enabled for this domain (default it is disabled)

6. CloudLinux LVE Manager

Increased PMEM

No effect

7. Restarted services

Restarted lsphp

Restarted LiteSpeed

Restarted Apache/httpd

No effect

8. I manually checked every possible PHP memory override file

I also checked and edited every file on the server that could potentially override memory_limit.
Here are the relevant files and their values:

/opt/cpanel/ea-php81/root/etc/php.ini → memory_limit = 512M

/opt/cpanel/ea-php81/root/etc/php-fpm.d/www.conf → php_admin_value[memory_limit] = 512M

/opt/alt/php81/etc/php.ini → memory_limit = 512M

/home/club4pnk/public_html/wp-config.php → ini_set('memory_limit', '512M')

/home/club4pnk/public_html/.user.ini → memory_limit = 512M

/home/club4pnk/public_html/php.ini → memory_limit = 512M

/home/club4pnk/public_html/.htaccess → php_value memory_limit 512M

/etc/php.ini → memory_limit = 512M

/var/cagefs/.../php.ini → still shows memory_limit = 128M (CloudLinux CageFS)

Despite all of these being set to 512M, WordPress still reports:

PHP memory limit: 128M

This makes me think the server is ignoring all PHP configuration files and forcing the CloudLinux ALT‑PHP defaults.

Symptoms

WordPress always reports memory_limit = 128M

Divi Theme Customizer crashes

PMPro activation crashes

/wp-admin/options-permalink.php crashes

phpinfo() shows the server is using alt-php81, not ea-php81

Temporary workaround

I restored plugins/themes from a 1‑week‑old backup so the older versions of PeepSo and PMPro work again.
But I need to update them soon, so I must solve the memory limit issue.

Question

Is there anything else I should check in a CloudLinux + LiteSpeed + cPanel/WHM environment that could force PHP to stay at 128M even after updating all INI files?

It seems LiteSpeed is using ALT‑PHP instead of EA‑PHP LSAPI, and all EA‑PHP settings are being ignored.
What is the correct way to force LiteSpeed to use EA‑PHP so that memory_limit can be increased?

Any guidance on what I might be missing would be appreciated.

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