Hello @Szymon,
Thank you for posting your query on Microsoft Q&A.The error message indicates that your account has been blocked in Azure, which is why you're unable to log in to the Azure Portal using your account.
To resolve this issue, please contact the global administrator in your tenant and ask them to follow these steps to unblock your account:
Sign in to the Microsoft 365 portal as an global admin.
Under Users, Select Active Users.
Locate the user, and then click the users Display name to open the settings pane.
At the top of the pane, select Unblock sign-in.
In the Unblock sign-in screen, de-select Block this user from signing in and click Save changes.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Thanks,
Chaithra E