Whoops on install

What we mean here is an internal code exception in an addon or the core when you click the install button from the Add Functionality dashboard page or when you visit a page after installing an addon package. 

If you experience such an issue, here are a few things you can check that may resolve the problem.

1. Php Version. Check your php version is compatible with the addon, For example, check if you are running php5.6 when an addon requires php7+. You can find the php version in the report at /dashboard/system/environment/info. As a general guide, if your site is ConcreteCMS version 8+ then aim to run on at least php7.2. (It will run on lower versions, but less efficiently)
2. Database Entities. ConcreteCMS uses a database abstraction layer called Doctrine. Doctrine works by creating proxy classes that map between php data and the database and sometimes these get out of step or muddled into a chicken and egg dilemma. The dashboard page at /dashboard/system/environment/entities has a switch to control when the proxy classes are regenerated. Try placing this into Development mode when installing an addon package (but remember to disable development mode to speed up a live site)
3. File Ownership. The web server 'user' needs to have ownership, or at least full permissions, to access the package files and directory. If it does not, either the package will not install, may partially install, or may install but leave debris behind which interferes with subsequent operation. Such permissions related problems are more frequently encountered on manual installation of packages, typically where the SSH or FTP user uploading the package is not the web server user.
4. Cache. ConcreteCMS makes extensive use of a number of different caching mechanisms to speed up web pages. When installing a package, sometimes outdated cached data causes issues with the install. Try disabling all the caches at /dashboard/system/optimization/cache when installing an addon package (but remember to re-enable the caches for a live site).
5. Theme. Most marketplace themes are well behaved. Nevertheless, sometimes a theme can interfere with an addon package, so try switching the site theme back to Atomik using /dashboard/pages/themes. You won't loose any content on the front of your site, but some page areas may not be shown until you swap back to your theme.
6. Middleware. Some addons implement middleware layers that manipulate pages before and/or after the main rendering of each page. If such addons are installed, there is a possibly they could interfere with the dashboard and other addon installation. Most such middleware implementations include condition checks to ensure they don't mess with the dashboard, but perhaps you can switch them temporarily off just to be sure.

If you experience a code error on or immediately after install and need assistance, please use the Send Message link from the addon marketplace page to report the problem. Assuming you have full error reporting enabled, on the error report,

• Prior to v9.4.0: click the [copy] button immediately below the error message.
• v9.4.0 and later: click the [Stack Trace] button and copy the content.

That will provide a stack trace you can paste into the help request and save time having to request that report later. There may also be details of an error in your site log at Dashboard > Reports > Logs.