Error on activating SumoMe plugin on freshly deployed WP droplet

Hi guys, I made a fresh Wordpress droplet. I didn’t do any changes. The Wordpress version is 5.8 and upon activating the SumoMe plugin, it throws the following error :

Plugin could not be activated because it triggered a fatal error. Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method WP_Plugin_SumoMe::activate_SumoMe_plugin() cannot be called statically in /var/www/html/wp-includes/class-wp-hook.php:303 Stack trace: #0 /var/www/html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters() #1 /var/www/html/wp-includes/plugin.php(470): WP_Hook->do_action() #2 /var/www/html/wp-admin/plugins.php(193): do_action() #3 {main} thrown in /var/www/html/wp-includes/class-wp-hook.php on line 303

Steps I’ve tried :

  1. Thinking it might be a corrupt installation, it reinstalled the droplet but that doesn’t solve.
  2. I also tried updating the Ubuntu packages, didn’t help.

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Bobby Iliev
Site Moderator
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February 28, 2022


It sounds like the plugin is not compatible with PHP 8.0 which is the PHP version that comes with the 1-Click WordPress installation.

Can you share a link to the exact plugin that you are trying to install?

Usually, in such cases, it might be best to reach out to the plugin developers and ask them to upgrade the plugin so that it is compatible with the latest PHP versions.

Alternatively, you could try installing an older PHP version like PPH 7.4 and trying out the plugin installation again.