hello, I followed step by step, the guide The Perfect Server - Ubuntu 16.04 from the howtoforge site, and it worked everything perfect for a year, then after some updates the problem came up and I can not fix it.
step To install Roundcube Webmail, run:
apt-get install roundcube roundcube-core roundcube-mysql roundcube-plugins roundcube-plugins-extra javascript-common libjs-jquery-mousewheel php-net-sieve tinymce