Originally Posted by JDP1970

In my situation I was already logged in to both the AF & KLM apps.

On the day in question, I'd logged in and out of the AF website on my Mac, I then logged out of AF app as suggested in order to get the home page of the app to reflect my updated status. I was then unable to log in to either the AF app or the AF/KLM websites. Fortunately, as I was still logged in to the KLM app, I was able to go in to my profile and resave my email address, I was then able to log in to the AF website via the use password method.

Are you seeing the invalid email message? If so & if you're still logged in to the website I'd suggest going in to edit your profile and saving your email address again.