null I have two @ULB email addresses. Which is the official?
You are newly registered* at ULB and have a 'firstname.lastname@ulb.ac.be' email address ? It is now replaced by a 'firstname.lastname@ulb.be' email address -without the "ac". This new address becomes your ULB official address and is accessible via Office 365.
To log in, enter your username in the format 'firstname.lastname@ulb.be' and the password you defined in Office 365 or received by private email for your first login.
Why two @ULB email addresses?
ULB has opted for a new mail system and is currently in a transition phase between it and the old one. Some time is needed before all procedures are adapted. During this transition phase, any message wrongly sent to your old 'firstname.lastname@ulb.ac.be' address will be automatically redirected to your official address 'firstname.lastname@ulb.be'.
Note: the "My personal data" tab of the MonULB portal will still temporarily display the old 'firstname.lastname@ulb.ac.be' address.
[* The definitive messaging 'firstname.lastname@ulb.be' is only given to students who are actually registered, that is to say having paid at least part of their registration fees.]