Package php5 has no installation candidate This occurs when following the second step on the instructions on the following link (just after Install all dependencies:) sudo apt-get install apache2 mysql-server mysql-client php5 libapache2-mod-php5 php5-mysql php5-curl php-pear php5-dev php5-mcrypt php5-json git-core redis-server build-essential. How to Install ownCloud 10 on Ubuntu 18.04 & 16.04 Step by step guide to install and configure owncloud 10 on Ubuntu 18.04, 16.04. I also notice that nap still seems to work? Try running 'sudo apt-get nap' and see if that works. I will have to dig deeper to find the real reason this is happening. If for some reason you have an old version, let me know and I can work around it:) This is a temporary fix.
These programs are made for Jessie systems, so you have to have the latest raspbian installed for them to work. There is a program called gdebi that installs the packages with the dependencies, so that will be installed when you run the following script/s alongside (hopefully) nap, ntpdate, and postfix.
Fix for postfix, ntpdate After searching the web for a while, I found the correct software.