Fatal error

Hi, I am getting fatal error, when a new user wants to sign up, if I disable your plugin, the error is not showing up

Fatal error: Uncaught Error: Call to a member function HashPassword() on null in /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/yaymail/includes/MailBuilder/Shortcodes.php:337 Stack trace: #0 /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/yaymail/views/templates/single-mail-template.php(29): YayMail\MailBuilder\Shortcodes->shortCodesOrderDefined(false, Array) #1 /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/woocommerce/includes/wc-core-functions.php(345): include(‘/home/httpd/vho…’) #2 /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/woocommerce/includes/wc-core-functions.php(364): wc_get_template(’emails/customer…’, Array, ”, ”) #3 /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/woocommerce/includes/emails/class-wc-email-customer-new-account.php(133): wc_get_template_html(’emails/customer…’, Array) #4 /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/woocommerce/includes/emails/class-wc-email.php(541): WC_Email_Customer_New_Account->get_cont in /home/httpd/vhosts/vge.li/lintumokki.com/wp-content/plugins/yaymail/includes/MailBuilder/Shortcodes.php on line 337