The interface is connected, but the Internet can’t be accessed

Currently working on my friend's router set up, it was working well for about a month with no issues and we realized it goes from being online to offline every 5 or so minutes, so I checked and got the "The interface is connected, but the Internet can’t be accessed", tried updating it and restarting it but no luck. Also have the logs if anyone needs to see them. Using B3000 on 4.5.19, connected to main router by ethernet.

link

Please provide additional information about this router and the connection.
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just provided needed information and updated the post