I get this issue about once a week - while watching a program the sounds just cuts out. I correct it by changing the channel and then going back to the channel I was watching and the sound comes back. Happens on all my TVs about once a week.
If I power off the box and turn it back on the volume is muted. I have to go into device settings/video display and re-select the 1080 option (that still has a check mark) in order for the volume to resume?
Here are my comments/questions.
1. Make sure the firmware in your TV is updated. If you're not familiar read the operating manual for how to do this for your particular make/model of TV. You may want to download the OM from the manufacturer's website and search the pdf for "firmware update" or similar.
2. Some TVs do not "shake hands" well over HDMI to the Rogers boxes even if updated. There are various audio setting possible in the Rogers box. Choose a different setting. I don't have Ignite, but there should be options similar to Dolby Digital, Other, advanced, or similar. Choose a different setting that will probably send PCM to the TV. This may help.
3. See post 6 of this thread for other possible suggestions.