Site very slow (front and backend)

PHP Fatal error:  Uncaught Exception in /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/includes/class-mailup-requests.php:142
Stack trace:
#0 /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/includes/class-mailup-model.php(495): Mailup_Requests->typeFields()
#1 /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/includes/class-mailup-model.php(186): Mailup_Model->prepare_api_request('typeFields')
#2 /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/includes/class-mailup-model.php(217): Mailup_Model->cached_type_fields()
#3 /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/includes/class-mailup-model.php(442): Mailup_Model->getTypeFields()
#4 /home/flagenda/public_html/wp-content/plugins/mailup-email-and-newsletter-subscription-form/public/class-mailup-public.php(146): Mailup_Model->get_fe_form()
#5 /home/flagenda/public_html/wp-includes/shortcodes.php(355): Mailup_Public->create_form('', '', 'mailup_form')
#6 [internal function]: do_shortcode_tag(Array)
#7 /home/flagenda/public_html/wp-includes/shortcodes.php(227): preg_replace_callback('/\\[(\\[?)(mailup...', 'do_shortcode_ta...', '[mailup_form]')
#8 [internal function]: do_shortcode('[mailup_form]')
#9 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Twig.php(296): call_user_func_array('do_shortcode', Array)
#10 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Environment.php(497) : eval()'d code(125): Timber\Twig->exec_function('do_shortcode', '[mailup_form]')
#11 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Template.php(453): __TwigTemplate_c94e025e8a882f13d9d15c277b816fc11f3ec1059cd852e50752d978f8eb4da3->doDisplay(Array, Array)
#12 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Template.php(420): Twig\Template->displayWithErrorHandling(Array, Array)
#13 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Template.php(432): Twig\Template->display(Array)
#14 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/TemplateWrapper.php(47): Twig\Template->render(Array, Array)
#15 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Loader.php(79): Twig\TemplateWrapper->render(Array)
#16 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(334): Timber\Loader->render('./intro-double-...', Array, false, 'default')
#17 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(383): Timber\Timber::compile('./intro-double-...', Array, false, 'default', true)
#18 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(410): Timber\Timber::fetch('./intro-double-...', Array, false, 'default')
#19 /home/flagenda/public_html/wp-content/themes/ragionatecisopra/homepage-v2.php(290): Timber\Timber::render('./intro-double-...', Array)
#20 /home/flagenda/public_html/wp-includes/template-loader.php(106): include('/home/flagenda/...')
#21 /home/flagenda/public_html/wp-blog-header.php(19): require_once('/home/flagenda/...')
#22 /home/flagenda/public_html/index.php(17): require('/home/flagenda/...')
#23 {main}

Next Twig\Error\RuntimeError: An exception has been thrown during the rendering of a template (""). in /home/flagenda/public_html/wp-content/themes/ragionatecisopra/views/intro-double-icons-block.twig:63
Stack trace:
#0 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Template.php(420): Twig\Template->displayWithErrorHandling(Array, Array)
#1 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/Template.php(432): Twig\Template->display(Array)
#2 /home/flagenda/public_html/wp-content/plugins/timber-library/vendor/twig/twig/src/TemplateWrapper.php(47): Twig\Template->render(Array, Array)
#3 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Loader.php(79): Twig\TemplateWrapper->render(Array)
#4 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(334): Timber\Loader->render('./intro-double-...', Array, false, 'default')
#5 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(383): Timber\Timber::compile('./intro-double-...', Array, false, 'default', true)
#6 /home/flagenda/public_html/wp-content/plugins/timber-library/lib/Timber.php(410): Timber\Timber::fetch('./intro-double-...', Array, false, 'default')
#7 /home/flagenda/public_html/wp-content/themes/ragionatecisopra/homepage-v2.php(290): Timber\Timber::render('./intro-double-...', Array)
#8 /home/flagenda/public_html/wp-includes/template-loader.php(106): include('/home/flagenda/...')
#9 /home/flagenda/public_html/wp-blog-header.php(19): require_once('/home/flagenda/...')
#10 /home/flagenda/public_html/index.php(17): require('/home/flagenda/...')
#11 {main}
  thrown in /home/flagenda/public_html/wp-content/themes/ragionatecisopra/views/intro-double-icons-block.twig on line 63
[06-Sep-2023 13:49:06 UTC] WP_Error Object
(
    [errors] => Array
        (
            [http_request_failed] => Array
                (
                    [0] => cURL error 28: Operation timed out after 5001 milliseconds with 0 bytes received
                )

        )

    [error_data] => Array
        (
        )

    [additional_data:protected] => Array
        (
        )

)

How to fix this?
PHP 8.1
WP 6.3.1
Themes frontend writte in with twig (using Timber)