Overview
Scheduled builds getting canceled when manual builds work fine can be due to the amount of traffic the site is receiving. WordPress does not have an active thread running so in orderfor a scheduled package to build it has to be kicked off and run when visitors are hitting your site. The simplified version is:

1. Visitor hits your site
2. As part of WordPress page processing, Duplicator Pro determines package needs to build
3. Package starts building

Option 1Sometimes the “ClientSlide kickoff” option can be turned on when it doesn’t need to be. A side effect of this option is that it causes builds to run slower and timeout.To determine its state and if it does not need to be on:

1. Go to Duplicator Pro > Packages > Advanced and see if “Client Side Kickoff” is enabled.
2. If it is enabled, uncheck it.
   • If it is NOT enabled, then skip the rest of these steps and go to option #2 client Side Kickoff is not a problem
3. Go to Duplicator Pro > Schedules, hover over your schedule and click “Run Now”
4. Observe if the package builds or gets stuck at a certain percentage.
5. If the package builds then you are good and the package should not time out.
6. If the package gets stuck/doesn’t build, re-enable Client Side Kickoff and proceed to the next option below.

Option 2Consider setting up a remote cron schedule that will generate consistent traffic to your site. For full details to this process seeHow to make my scheduled build run on time?

Option 3If there is very light traffic occurring when the schedule is supposed to run, the package build can actually time out. To resolve this, do the following:

1. In Duplicator Pro > Settings > Packages set Server Throttle to Off or Low at the most
2. In Duplicator Pro > Settings > Packages set Max Build Time to at least 270 Minutes
3. Set your schedule build time to a time when you will be getting a decent amount of traffic

Also, since you are setting the start time to occur during a period when you get more traffic we recommend Server Throttle be turned on – this will ensure your visitors are minimally impacted by the processing of the backup.

Option 1When running multiple Duplicator plugin instances on the same server (on some hosts), the PHP process (depending on architecture) might have conflicting overlaps. Since each site buildsthe package file independently, they may interfere with one another. Some web servers are setup in such a way as to only handle the activity on one site at a time (this is not commonon most hosting platforms).

A quick fix for this is to switch your schedule start time on each site. Make sure each site has a unique daily start time so if all of your sites are set to run at 1am, then try tooffset each one by X hours.