Recipient address rejected: Sorry, too many emails

HI,
I moved my site on Ovh hosting. I configured the settings and I received test email, but I get no other email. The mail service works properly (webmail).

In the email log always I see this error:
5.7.1 Recipient address rejected: Sorry, too many emails

This is the log after diagnostic test:
OS: Linux webd243.cluster020.gra.hosting.ovh.net 3.14.79-grsec-hosting-web-3.14 #1 SMP Thu Oct 20 14:47:42 UTC 2016 x86_64
PHP: Linux 5.6.25 en_GB.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=Yes, zlib_encode=Yes
WordPress: 4.7.1 it_IT UTF-8
WordPress Theme: Jupiter
WordPress Plugins: Artbees Themes Captcha, iThemes Security, Cookie Law Info, Google Tag Manager for WordPress, Envato WordPress Toolkit, WPBakery Visual Composer (Modified Version), Master Slider Pro, My Custom Functions, Popup by Supsystic, Postman SMTP, Slider Revolution, WPML Multilingual CMS, WooCommerce Advanced Free Shipping, WooCommerce – Store Exporter, WooCommerce Multilingual, WooCommerce PDF Invoices Italian Add-on, WooCommerce PDF Invoices & Packing Slips, WooCommerce Product Categories Selection, WooCommerce Stock Manager, WooCommerce, Yoast SEO, WP Migrate DB, WPML Media, WPML Sticky Links, WPML String Translation, WPML Translation Management, MailPoet Newsletters, YITH WooCommerce Category Accordion, YITH WooCommerce Dynamic Pricing and Discounts
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email
WordPress phpmailer_init Action(s): WC_Email_New_Order->handle_multipart, WC_Email_Cancelled_Order->handle_multipart, WC_Email_Failed_Order->handle_multipart, WC_Email_Customer_On_Hold_Order->handle_multipart, WC_Email_Customer_Processing_Order->handle_multipart, WC_Email_Customer_Completed_Order->handle_multipart, WC_Email_Customer_Refunded_Order->handle_multipart, WC_Email_Customer_Invoice->handle_multipart, WC_Email_Customer_Note->handle_multipart, WC_Email_Customer_Reset_Password->handle_multipart, WC_Email_Customer_New_Account->handle_multipart
Postman: 1.7.2
Postman Sender Domain (Envelope|Message): mysite.it | mysite.it
Postman Prevent Message Sender Override (Email|Name): No | No
Postman Active Transport: SMTP (smtp:none:plain://smtp.mysite.it:587)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 4516 | 84