I have been receiving these emails lately, even though I haven't used AMEX since December '23. The communication is solely via email; I haven't received any SMS. I plan to contact AMEX tomorrow regarding this matter. I'm curious if anyone else is experiencing the same issue.
This otp does not come for other type of cards visa or master diners network. Amex card only has this issue. I have not seen for type of cards getting otp which could rare.