mailpoet 3 not send newsletters – help!

Hello
We have problems with mailpoet 3

The preview of the campaigns, when we are creating the newsletter, works well.
The SMTP shipping system works well.

But when we click on the “send” button to send to the subscribers list, then the shipment remains at 0% without sending.
It takes hours and hours and does not send anything.

I tried setting up the settings with the two options of Newsletter task scheduler (cron). But neither work well.

Please can you help me?

Thanks.

PHP version: 7.0.22
MailPoet Free version: 3.0.1
MailPoet Premium version: N/A
MailPoet Premium/MSS key: 
WordPress version: 4.8.2
Database version: 5.5.57-0+deb7u1-log
Web server: Apache
Server OS: Linux vxhci-17.srv.cat 3.2.0-4-amd64 #1 SMP Debian 3.2.84-2 x86_64
WP_MEMORY_LIMIT: 256M
WP_MAX_MEMORY_LIMIT: 192M
WP_DEBUG: false
PHP max_execution_time: 30
PHP memory_limit: 192M
PHP upload_max_filesize: 15M
PHP post_max_size: 15M
WordPress language: ca
Multisite environment?: No
Current Theme: Leader Ponent Web (version 1.2.0)
Active Plugin names: goodbye-captcha/goodbye-captcha.php, gravityforms/gravityforms.php, advanced-custom-fields-pro/acf.php, autoptimize/autoptimize.php, custom-post-type-ui/custom-post-type-ui.php, duplicator/duplicator.php, easy-theme-and-plugin-upgrades/init.php, easy-wp-smtp/easy-wp-smtp.php, elementor-pro/elementor-pro.php, elementor/elementor.php, events-manager/events-manager.php, genesis-title-toggle/genesis-title-toggle.php, genesis-translations/genesis-translations.php, google-analytics-for-wordpress/googleanalytics.php, iwp-client/init.php, kt-funcions-extra/kt-funcions-extra.php, mailpoet/mailpoet.php, monarch/monarch.php, regenerate-thumbnails/regenerate-thumbnails.php, simple-social-icons/simple-social-icons.php, updraftplus/updraftplus.php, user-role-editor/user-role-editor.php, widget-css-classes/widget-css-classes.php, wordfence/wordfence.php, wordpress-seo/wp-seo.php, wp-super-cache/wp-cache.php
Sending Method: SMTP
Sending Frequency: 25 emails every 10 minutes
Task Scheduler method: MailPoet
Cron ping URL: https://www.leaderponent.cat?mailpoet_router&endpoint=cron_daemon&action=ping
Total number of subscribers: 832