I have a problem that I get Please configure your DNS manually. every time I leave a screenshot

but apart from that my internet works fine when I had another TP Link connected but it is already old and I wanted to buy this one that comes with the DSL input but it drops too much the internet is not stable I need help

my internet drops like every 10 minutes it is literally unusable. I bought it 2 weeks ago and it didn't work for more than 24 hours every time it says please configure your dns manually. I tried to configure it to 8.8.8.8 and 8.8.4.4 and it didnt work i tried every thing and it does not work.