Why can't I log into my account on Sims 3?

krungyi1005  You shouldn't need to login to play Sims 3 or use your custom worlds.  If you don't try to login, are your worlds missing, or do you select them but they don't load?

For the login issue itself, if your password has special characters, please remove them.  Either way, please delete the file labled [your email].bin inside Documents > Electronic Arts > The Sims 3, and also clear Edge's Internet Explorer-mode data.  Even if you never use Edge, the launcher does for some purposes.  Instructions are towards the end of this article:

https://support.microsoft.com/en-us/microsoft-edge/view-and-delete-browser-history-in-microsoft-edge-00cf7943-a9e1-975a-a33d-ac10ce454ca4

my worlds show up on the start screen, but when i click on one to try and load it, it still shows the gold money sign in the corner, as though i haven't already purchased it. i'll try the delete history thing you've linked!

krungyi1005  Right, that's just the in-game shopping experience, nothing about whether you own the worlds.  I see that too when I haven't disabled the feature and when my worlds aren't installed.

As a test, please try installing one world into a new user folder.  Move the existing Sims 3 folder out of Documents > Electronic Arts, or rename it, whichever you prefer, and when you open the launcher, a clean folder will spawn with no content.  Your saves and other user data will be intact but not read by the game.

Download one world and let me know whether it installs.  If you get a message that you don't own it, try downloading from its product page rather than your purchase history, and try refreshing that page a few times.  I use Firefox with the Store, which seems to work best overall.

If you still can't install the world, let me know.  If you can, load the game and see whether the world itself loads properly too.