Revert "turn off begin/rescue loop in mailman_server script (#5840)"

This reverts commit d084918.

script/mailman_server

@@ -23,19 +23,18 @@ Mailman::Application.run do
   # routes are written here
   # route for mail having node with id in their subject will only be accepted for processing
   default do
-# REMOVING ENTIRE 'begin/rescue' loop to try to address mailmain issues
-#     begin
-#       retries ||= 0
+    begin
+      retries ||= 0
       # do something with the database that does not fetch mails yet (let's try to ensure we have a MySQL connection first)
       puts Comment.last.inspect
       Comment.receive_mail(message)
-#     rescue Exception => e
-#       Mailman.logger.error "Exception occurred while receiving message:\n#{message}"
-#       Mailman.logger.error [e, *e.backtrace].join("\n")
+    rescue Exception => e
+      Mailman.logger.error "Exception occurred while receiving message:\n#{message}"
+      Mailman.logger.error [e, *e.backtrace].join("\n")
       # Seeing major site slowdowns; commenting out for now; 
       # https://github.com/publiclab/plots2/issues/5817
       # retry if (retries += 1) < 3
-#     end
+    end
   end
 
 end