Error installing Theme on GoDaddy Drupal 8.4.5 I have goDaddy and installed Drupal 8.4.5, the newest version they have on their Installation. Trying to install the theme Nexus, when I upload the theme from archive (zip file) and click install I get the following error.


  The website encountered an unexpected error. please try again later.


I have tried clearing the cache. I was running Drupal 8.3.2 and it would just go to a blank screen; updating to Drupal 8.4.5 now got me to this error. I have downloaded and tried about 20 different themes. I either get this error or I get that the file is over 2 megabyte and is too big. What am I doing wrong or how do I fix this error?
Based on the two errors you noted:


"The website encountered an unexpected error. please try again later."
the file is over 2mb


It sounds like your web-hosting provider/CPanel account has a limit on file uploads set, and: 

a) your Drupal Core update/upgrade wasn't completed successfully

b) you may not have a temporary directory configured properly for unzipping the theme archive.



Recommended course of action would be to:


finish your Drupal 8.4.5 upgrade (or perform a fresh install on GoDaddy).  If you're drupal core codebase was updated, be sure to go to update.php to ensure all Drupal database updates were applied.
Once Drupal Core has been updated and you can navigate the site/add test content successfully, unzip the theme codebase locally and upload the "nexus" folder to your Drupal site's /themes/custom/ folder using either GoDaddy's file manager, ftp, or via version control tools such as git.
With the theme folder manually installed to the server, flush the cache of your Drupal site; go to Appearance, select and enable the Nexus theme.