Hello, I'm trying to install new extensions from magento web setup wizard. The platform is running on a dedicated server.
This is what I get. I'm beginner on magento and I need help.
okay i understand as a beginner sometimes its difficult to debug the issue.
You have issue of server settings which is not properly configured and that is why you are facing this issue , Like on your server cron is not configured/activated so you must required cron to be configured on server.
Second important thing is that on your server few PHP extensions are missing , so you required to install/enable those extension on your server.
As you said your platform is running on dedicated server , so your server/hosting provider does this job for you , you can raise a ticket over there.
here i am sharing link , for minimum requirement needed for web setup wizard - http://devdocs.magento.com/guides/v2.2/install-gde/install/web/install-web.html
On this doc - Before you start your installation - topic is there , make sure you have full-fill all those pre-requisite requirements.
Hope it helps