@tsecniw_ Does your computer run Windows or macOS? For Windows, the issue could be that the external drive has a different letter now than it did when you created the symbolic link (I'm guessing this is what you did). The fix here is to plug in your external devices in the same order as before so they receive the same letter; the letters are assigned anew each time Windows recognizes a new device. MacOS doesn't have this issue.
To reverse the process in Windows, you can simply delete the symbolic link you created and move the user folder back to your internal drive. Please see "reversing the symlink" in this guide for macOS:
https://bluebellflora.com/saving-your-sims-4-folder-to-an-external-drive/
Use the above guide for macOS if you'd like to recreate the symlink at some point, or use the guide below for Windows.
