Hello @antoniocapunime ,
Welcome to the MS Q&A forum.
Error failure 53003 means your sign-in request was blocked due to a conditional access policy configured on the Tenant where you tried to authenticate. Means, Tenant Admin configured CA Policy to control what a specific user can access, and how and when they have access: block user/group membership or block based on the specific location/device/application, etc. You should consult with the business' IT administrator of this Tenant to check for Azure Conditional Access Policies that are applying to you and your account.
Below references to articles where you could find more detailed information about this sign-in failure and access control policies which were used to block this sign-in:
Hope above answers your question and concern. Let me know if you need additional assistance. If the answer was helpful, please accept it and complete the quality survey so that others can find a solution.
Sincerely,
Olga