FedEx customers are complaining that the company's system for tracking packages has been crashing.

FedEx Corp. said in statement Monday that it was dealing with sporadic issues and was trying to fix them.

A spokeswoman said the Memphis, Tennessee-based company expected operations to return to normal shortly. She declined to describe the extent of the problem or say whether the company had identified the cause.

We are addressing some functionality issues and are working to resolve as soon as possible. We sincerely regret any inconvenience. —@FedEx

Downdetector, a Dutch web-monitoring firm, says complaints started early Monday and rose through midday.

Max Dushey, who owns a fulfilment-software company in New Jersey, says in an interview that the problems seem intermittent. He says some small customers have worked through the problem but his large wholesaler customers haven't been able to print mailing labels to meet orders from retailers.