drush Invalid argument supplied for foreach() backend.inc:709

Question

I have aegir setup, I'm trying to cache clear on all the sites in remote platform machine but failed with below error.

drush @sites cc all
You are about to execute 'cc all' non-interactively (--yes forced) on all of the following targets:
Continue?  (y/n): y
Invalid argument supplied for foreach() backend.inc:709 

Would be great if some one had any idea to overcome.

Answer 1

The cause of above error is that @sites is returning no sites.

Try drush sa @sites too, and see what it says.

Note, however, that @sites refers to all of the sites in a multisite install; it does not refer to all of the sites in your aliases.drushrc.php. If you rename your aliases file to foo.aliases.drushrc.php, then @foo will reference all of the aliases in that file.

Else check this as well: https://www.drupal.org/node/1031170

Reference:
https://www.drupal.org/node/161698