Why can't I use safari and some app's on WIFI

After I updated my Iphone 6+ with the last update 12.2 a few months ago I had issues with some app's not updating only when on WIFI. I googled the problem and can't remember exactly what I did - it might have been turning power off/on and toggling the WIFI button. It worked after that. Now a month or so later I have am now not able to access Safari "because the server cannot be found". Also Instagram and Facebook don't fully load. They all work when I am on my phone's network. I have been googling this and trying different things such as what I did before and also turning bluetooth off/on, clearing browser history. I have lots of space so that isn't the problem. This has been for 3 days. I did read that some users had problems after logging in to websites using Safari - I did log in to a website just before this happened and had a few problems when logging in but eventually was able to access the website. If I reset the network settings will I lose contacts, email set up, etc? I am hesitant to do it because I am not a techi. Help please!!