Try a different HDMI cable.
Does it do this with all sources?
If it doesn't then try changing the HDMI cable from that source or a different input on the receiver.
Some Onkyo receivers have had issues with HDMI and are covered by an out of warranty free repair.
https

/www.hometheaterforum.com/community/threads/onkyo-offering-to-repair-receivers-2009-2012-hdmi-issues.335227/