The php temporary directory is not set.
Joomla is installed on Synology NAS. The warning about the temp directory not being set, I thought of as being a problem within Joomla. So within Joomla I checked the server tab and checked if the temp file is set. I then FTP into the Joomla folder to check if the file is available and has the correct rights set. It did and the rights are set to 755. But still the warning. However, I have no issues with downloads of plugins etc within Joomla. Is there still something I need to do within PHPmyadmin? I will then need a step by step manual as I am new with the program.