Hi @Gonzalo Espinosa , when the sameSite attribute is set to strict, the browser will only send the cookie in a first-party context, which means that the cookie will only be sent to the same site that set it. This can cause issues with cross-site authentication flows, such as the one used by passport-azure-ad. This document details possible solutions.
Please let me know if you have any questions and I can help you further.
If this answer helps you please mark "Accept Answer" so other users can reference it.
Thank you,
James