Fatal error: Cannot redeclare beonepage_contact_send_message

Hello,
I would like to report following issue:

Fatal error: Cannot redeclare beonepage_contact_send_message() (previously declared in /data/web/virtuals/156826/virtual/www/wp-content/themes/beonepage-lite/inc/extras.php:178) in /data/web/virtuals/156826/virtual/www/wp-content/plugins/beonepage-lite/beonepage-lite-plugin.php on line 97

The website has not been used for some time. So I have made backup and thed updated all the plugins and this error message occured and the site is down.
Could you please advice how to fix this?

Thank you very much.