An investigation will be conducted after some Ontarians did not receive the emergency alert that was sent to their phones as part of a test of the system on Wednesday.

The alert was supposed to be delivered to all Ontarians at 12:55 p.m.

But some Ontarians have since reported that they did not receive it, according to Alert Ready.

“We can confirm the test was issued and distributed to television, radio and compatible wireless devices. We are aware that some Ontarians are indicating they did not receive the test alert on their wireless device. Our wireless partners are working to identify the issue,” the organization said in a message posted to their website. “Testing the end to end system allows us to ensure it is working as intended and to learn what areas need adjustments – in order to continuously enhance the system. Ongoing testing is an important step to ensure safety for all.”

The emergency alert system is typically tested twice a year, in both November and May.

Since first being launched in 2015, a total of 22 emergency alerts have been issued through Alert Ready in Canada, including four in Ontario.