Can't connect to the gallery/go online

@wayward_daugther  Is the EA App itself loading properly?  Please check if you haven't already: open the App without launching Sims 4, and see whether your game library loads as normal.

If that's not the issue, does your computer have wifi?  If so, please set your phone as a mobile hotspot, with the phone using data rather than your home wifi, and connect the computer to that.  Simply accessing the event rewards panel shouldn't use much data at all, and you'll know right away whether this helps.  If it does, try powercycling your router.

@puzzlezaddict Thank you kindly for responding but unfortunately neither worked! I found a tweet from EA saying some users are having problems since this latest patch they're working on fixing... I hope this is what they meant. I have no idea what the point of being so cryptic about which problems exactly.

@wayward_daugther  If you use a third-party antivirus, try disabling it, temporarily of course, to see whether it helps.  As long as you don't do anything else at the same time, your computer should be safe.

Separately, as a way of cutting through a lot of potential issues at once, please create a new admin Windows account and play there.  Make it local, as in, don't link it to your email address or any other.  (You can choose "I don't have this person's info" and "create an account without an email" or similar.)  You'll be able to launch Sims 4 without reinstalling anything, but your saves and other user data won't be available.  That's fine for now and can be addressed later if necessary.

I don't think this is exactly the issue EA was alluding to with the tweet, although a fix could cover your particular issue as well.  Either way, it'll take a while for the rest of us to find out.