Device42 can collect warranty information for Dell, HP, and Lenovo devices from their vendor's API. If there is a case where the proper API tokens have been supplied but some devices are missing their warranty data without any job errors then the issue may be related to the vendor information.
The way that the warranty syncs work is that all devices using hardware models with the associated vendor (Dell in this example) will have their serial numbers run against the vendor API. If there are devices that do not have a hardware model, or that do not have the vendor name associated with the hardware, then they will not be checked in the sync.
Navigate to Datacenter > Vendors and search for "Dell":
If there are several variations of the vendor name they will have to be merged. Select all of the various Dell vendor names and click on the action dropdown on the top center of the page. The option to merge selected vendors will allow you to select a master record:
The master vendor name can be any of the ones on the list as long as "Dell" is either the master or added as an alias. After applying this change you can run the warranty sync again and any hardware that had a different "Dell" variation for a vendor name should be synced.