@puzzlezaddictYes, I own The Sims 3, but I had to uninstall it due to lack of space. I had it on Steam, and this issue seemed to have appeared after uninstalling The Sims 3. I will try it with my phone as a internet hotspot but it’s usually worked just fine with our home wi-fi.
EDIT: I did some searching on the Internet, and apparently the Activation64.dll is a DRM file by EA, which is apparently supposed to protect copyright. I don't understand why my PC is reporting it as missing/not working, as my copy of The Sims 4 is legitimate. I really need help with this. Should I just uninstall both The Sims 4 and Origin, clean the registry from any traces of them (I would also like some help with that) and then reinstall both? I'm so confused... I've tried everything!
EDIT 2: I tried the phone hotspot but it also didn’t work. I also have an old install of The Sims 4 on my old disk drive, but that didn’t seem to cause any problems before. Should I try reinstalling The Sims 3 though?