Hi @Domagoj Grguric ,
Welcome to our Q&A forum!
Answer your second question:
Why does disabling the Exchange Online (Plan 1) license still allow the user to sign into his email?
If you disable the Exchange Online (Plan 1) license for a user, the user will still be able to sign in to his or her e-mail account, but the account will be in a disabled state. This means that the user will not be able to send or receive new e-mails, create new calendar items, or access any of the Exchange Online features. However, the user will still be able to access the existing e-mails and calendar items that are stored in the mailbox. This is done to preserve the user’s data and allow the administrator to restore the license if needed.
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