It seems to have started at 10:00 PM last night local time and its ongoing. The entire mobile network in Canada has collapsed. The outage affected 10.2 million Rogers customers.
Given the scale of the outage it suggests it may be a malicious attack. Each common carrier is interconnected but there is a large level of redundancy to keep the network operating in case of a disaster. A national outage is definitely up there with an all out nuclear attack to cause that much disruption.
The mobile phones are showing no cellular service at all. Even a dead unused SIM card will allow a person to call the carrier to inquire about services but they are all down.
Customer service lines are all busy with inquiries. Check your phone to see if the cellular signal is back as a sign the services have been restored.
Cellular signal was restored at about 2:00 PM but SMS messages do not work. Rogers had apparently installed some updated software on their Ericsson 5G cellular systems on a national basis. This led to the widespread outage.
SMS messages returned to service at 4:40PM local time. Total downtime about 20:40 minutes. Services should be fully operational over the next few hours.