Is there a way to debug foreman/puppet error on Redhat 6.x (or 7.x)?

One day I got a lot of messages on puppet master (runs with
apache+mod_passenger) I see a lot of error messages like this:

Jul 19 19:35:26 foreman01 puppet-master[4095]: Report processor failed:
Could not send report to Foreman at execution expired

but I got almost no clue how to begin, after looking at httpd configs, I
followed the rails convention (newbie to rails)

1, view file /usr/share/foreman/config/routes.rb, and find the line like:

post "reports/create"

2, view the file /usr/share/foreman/app/controllers/reports_controller.rb
and find the function 'create':

def create
Taxonomy.no_taxonomy_scope do
if Report.import params.delete("report") || request.body
render :text => "Imported report", :status => 200 and return
render :text => "Failed to import report", :status => 500
rescue => e
render :text => e.to_s, :status => 500

Then I got stuck here, it doesn't seem much fruitful, how can I figure it
out that this function send out
error message 'exectution expired'?

Please shed a light and many thanks.