OnePlus 3T can't connect to new router

I recently got a new router it's the same model as my previous one. My phone won't connect to it, it'll just say optaining IP address. It will eventually connect if I use my data and watch like 10 mins of YouTube.

But it'll still eventually disconnect after a short while. I've tried nearly everything apart from a full factory reset and I'd really rather not do that.

Any help is appreciated, thanks.