My model is TL-WA850RE

Roughly a month ago I bought this range extender to plug ethernet into it because my wifi adapter wasn't very good, had really bad ping. It was working fine until at some point it stopped connecting to my internet, like it completely forgot it. I tried resetting it to factory settings and re-configuring it but it just wouldnt detect my internet. I tried doing it via WPS and it didnt work, and when I used the tether my app my wifi wasn't on the list, and adding it manually did nothing either. I heard that maybe I might need to mess with the mac filtering on my router's website, which I'm not sure what exactly does but it shouldn't be the problem since I never messed around with it before (I have tried to solve it this way however but I didn't really know what I was doing).

Sorry if I didn't make things very clear but I don't want to replace this because I don't know if that would actually fix anything because it could just be something with my wifi

Thanks