What you can try is exit Origin. - If exiting Origin isn't working, open Task manager (Ctrl-Shift-Esc) search for a file called ts4.exe. Click on it and select end process.
Restart the computer and try again.
If the above doesn't help, try moving your Sims 4 folder to the desktop [Click on the Sims 4 folder and select Cut and paste it to the desktop.]
Start the game, so it creates a new/fresh Sims 4 folder.
Log into Origin again, and try downloading the Sims 4 content packs again.
If Origin doesn't automatically start downloading the packs, Click the More tab (it's a little under the Play button) Select either Expansions Packs, Game Packs or Stuff Packs, and if any of them are showing as uninstalled, click the Install button.
If that goes okay, start to put back the other files and folders. (list of files and folders below).
- Options.ini (User game settings)
- Tray Folder (Sims/Houses/Commercial lots and rooms)
- Screenshots/Videos/Custom music
- Rest of the save games, if any.
(leave out slot_00000001.save which is the autosave. It is not used anymore.)
- Custom content like clothing, hair, skins, makeup
- Mods (Put these back one by one to make sure they all still work)
Please note some mods and custom content become outdated with every game patch released. This means you'll need to go through your mods folder to find what needs to be replaced.
Finding Problem Mods and CC
http://simswiki.info/wiki.php?title=Game_Help:TS4_Finding_Problem_Custom_Content
Resetting the game to factory settings without reinstalling
https://answers.ea.com/t5/Technical-Issues-PC/READ-FIRST-Troubleshooting-your-Game/m-p/3621199#Resetting