If you're logging in with FB, go to your Profile, Settings and Privacy, Apps and Websites and delete the entry for iFeis.
For Google login, go to your Account (click on the circle at the top right), then Security, Signing In with Other Sites (signing in with Google), Scroll down to find iFeis and remove it.
Then reconnect to iFeis and sign in. It will require you to go through the authorization step again, so you'll need your FB or Google password. Select “Accept” when prompted by the Google or Facebook