I tried to replicate your problem, but RootsSearch is working OK for me.
I went to a profile, clicked the RootsSearch link, and logged in. Then on the main RootsSearch page, I clicked on the "More sites" link at the lower right. That took me to the page where I could Enable or Disable certain websites. I disabled MyHeritage and enabled AmericanAncestors. Then I used my browser's back button to go back to the first screen, and the list at the bottom of the screen included AmericanAncestors instead of MyHeritage. And when I clicked on a link at the bottom of the screen, I got search results from the website I expected to get results from.