your first screenshot of the email I should trust. representing the Amsterdam time.
Second & third screenshot is of the academy portal; showing the time in boston.
So both are correct. See https://www.worldtimebuddy.com/
IST: 19:30
To be sure, email academy@mendix.com
Amsterdam is 1 hour ahead of GMT.
India is GMT +5:30, so IST is 4,5 hours ahead of Amsterdam. So 15:00 Amsterdam time is 19:30 India time.