The Toronto-based technology company issued a statement saying there was nothing to suggest the outage was related to a cyber attack.
It remains unclear how many businesses and transactions were affected, but data provided by Downdetector.ca indicated complaints had come in from across the country.
In a statement provided to The Canadian Press, the company said the outage lasted about 90 minutes.
"We have resolved the network outage and returned transaction processing to normal," the statement said. "We continue to investigate the root cause of the issue. There are no indications this appears to be cyber-attack related and all transaction systems are functioning normally again."
The company, a joint venture between Royal Bank and BMO Bank of Montreal, said transaction processing could be slow as its systems catch up with the backlog.