Who this is for: Wi-Fi phones, cordless handsets, and phones or tablets running the Cannon VoIP app on Wi-Fi.

What goes wrong

Why it happens

To save power, access points and devices can let a device "sleep" and only check for traffic now and then.

If a call arrives while the phone is asleep, the access point holds it until the phone wakes up. That delay can mean late rings or missed calls.

Sign in to your Wi-Fi system and look for power saving settings such as Green Mode, Eco Mode, Power Save, or scheduled radio shutoff.
Turn off scheduled Wi-Fi shutoff during business hours (and after hours if anyone takes calls then).
Look for a setting called DTIM interval and set it to 1 or 2 on the network the phones use. It controls how often sleeping devices are woken up. Higher numbers save power but delay calls.
On cordless handsets, turn off any Wi-Fi power saving or battery saver setting in the phone's settings.
On phones running the app, allow the Cannon VoIP app to run in the background and turn off battery optimization for it.
Restart the handsets.

On most home and small office routers, look under Wireless > Advanced for Green Mode, Power Saving, or Wi-Fi schedule.
On most business Wi-Fi systems, look in the SSID or radio settings for DTIM, Power Save, and Wireless Schedules.
On most mobile phones, battery optimization for an app is under Settings > Apps > Cannon VoIP > Battery.

Call each Wi-Fi handset several times while it's been idle. It rings right away every time.
Calls to the app ring on the first try when the phone is locked.
The first words of each call come through.

Still having trouble? Contact Cannon VoIP support at 888-973-0515 or support@cannonvoip.com.