Looks like there is an issue with the Modern History TV channel/app.
The only contact I see is for a Facebook link https://www.facebook.com/modernhistorytv1/.
There was also a Twitter account here but no interaction since 2019. https://twitter.com/ModHistoryTV.
Link to the website is also not working. https://www.modernhistorytv.net/apollo-11/
Perhaps see if you can make contact with Paul Viner (the creator of the channel) over there on Facebook.
The creators/developers of the different channels/apps on the Roku platform are responsible for the maintenance and fixes to their channels. May just be having some temporary issues.
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