(Reuters) -Exchange operator Nasdaq on Wednesday resolved a system issue that impacted stock orders and affected over 50 clients after rolling back the concerned application to a previous version, according to a notice on its website.

The incident started around 14:31 ET (1931 GMT) on Dec. 13 after the Nasdaq's 'FIX/RASH order' handling system experienced an issue caused by a duplicate internal order ID, the notice said.

FIX or Financial Information Exchange is a message protocol that defines an electronic message exchange for communicating securities transactions between two parties.

While investigating the issue, Nasdaq decided to shut down the FIX/RASH order handling system, block all new orders, and cancel any open orders back to customers, as per the notice.

"Nasdaq is confident that the corrective action fully addresses the issue and is ready for tomorrow's trading."

Some customers saw inaccuracies and delays in the delivery of execution reports, the exchange operator said in an emailed statement earlier on Wednesday.

"FIX/RASH was closed down for the rest of the day. The closing cross was completed and all other markets are operating normally," the firm said.

It did not respond to a request for comment on the number of trades affected during the system error.

(Reporting by Rishabh Jaiswal and Baranjot Kaur in Bengaluru; Additional reporting by Devika Nair; Editing by Sherry Jacob-Phillips and Sonia Cheema)