My friend who is an Indian citizen is unable to check in online in the KLM airlines website. She gets an error similar to somthing like this:
Unfortunately, it is not possible to check in because we have not yet received confirmation that your ESTA application was approved. Residents of countries under the Visa Waiver Programme need to have ESTA travel authorization for travel to or via the United States
Why would she require an ESTA to travel? She has a valid B1/B2 visa and this is her second trip to the United States.