Hi Paulo,
To help partners protect their businesses and customers from identity theft and unauthorized access, we activated more security safeguards for partner tenants. These safeguards mandate and verify MFA. Mandating MFA helps partners to secure their access to customer resources against credentials compromise.
Partners participating in the Cloud Solution Provider (CSP) program, Control Panel Vendors (CPVs), and Advisors must implement the Partner Security Requirements to stay compliant.
Partners are required to enforce MFA for all user accounts in their partner tenant, including guest users. Users must complete MFA verification for the following areas:
https://learn.microsoft.com/en-us/partner-center/partner-security-requirements-mandating-mfa