I am getting the following error when I try to activate the plugin…
Parse error: syntax error, unexpected ‘:’, expecting ‘;’ or ‘{‘ in C:\wamp64\www\intranet\wp-content\plugins\ajax-search-pro\includes\classes\Database\Manager.php on line 47
Your PHP version is very likely outdated. The error refers to a function type declaration, which was not supported before PHP 7.0. I recommend updating to the latest PHP if possible (8.x), as the minimum stable requirement for WordPress is 7.4 major version. This plugin also follows this requirement.
Updating to 7.4 or later will resolve any issues.