I am having the same issue with the 50" Onn Roku TV. The issue started with the latest software update 9.2.0 Build 4501 on Sunday, December 1st.
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Thanks for the inquiry.
Please contact your TV's manufacturer directly to report this issue and request additional support. Each Roku TV manufacturer provides direct support for their products running the Roku OS.
You can reach ONN support here: 1-800-966-6546
Thanks,
Danny