AccelerateWP "Redis Object Cache" plugin is not installed

Issue

• Attempt to install "Redis" from AccelerateWP fails with the following error:

  Misconfiguration
  "Redis Object Cache" plugin is not installed
  
  The "Redis Object Cache" WordPress plugin is not installed. Caching does not work

Environment

• AccelerateWP

Solution

Ensure that alt-phpXX-pecl-ext package is installed, where XX is PHP version for the particular domain used 

Cause

Redis PHP extension was not installed