Rather than risk having their systems clogged with packages, both FedEx and UPS are holding a harder line by enforcing a preset limit on the daily number of packages they will pick up. The policy is creating backlogs in some of the shippers' warehouses, affecting retailers as large as Costco Wholesale Corp. down to small- and medium-size companies.
For consumers, that means deliveries could arrive late, and anyone determined to get a gift delivered by Christmas needs to order it today without having to pay extra shipping fees
FedEx, UPS Are Managing Surge in Packages With Strict Limits on Shippers — Update | Morningstar