What's more, officials told NBC that United's computer problems and this incident are unrelated and neither appears to be part of a cyber attack. The exchange confirmed the lack of ties to cyber crime on Twitter, stating that the issue was internal, rather than the result of a breach. It added that while trading had been suspended, NYSE-listed securities could still be traded at other places -- like Nasdaq.

Update: Activity is scheduled to resume at 3:05 PM ET for NYSE Market (Primaries only) and 3:10 PM ET for the NYSE, and will do so without a re-opening auction. Closing auction is set for its normal time. There's still no word on the exact cause of the problem.

(1 of 3) The issue we are experiencing is an internal technical issue and is not the result of a cyber breach. — NYSE (@NYSE) July 8, 2015

(2 of 3) We chose to suspend trading on NYSE to avoid problems arising from our technical issue. — NYSE (@NYSE) July 8, 2015