Ok..
tried two different sites
Open Keychain Access. Delete the keychains for those sites.
*Relaunch Safari* and try logging into one of those sites again. You should be prompted to save your user name and password again. If so, just click Yes.
If that doesn't help, open a Finder window. Select your Home Folder in the Sidebar on the left. It has a small house icon. Then open the Library folder, then open the Preferences folder.
Move this file to the Trash:
com.apple.keychainaccess.plist
Restart your Mac.
🙂