Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Dear KALLIOPI KOKKINAKI
Good morning to you and thank you for your post in the Microsoft community.
I am writing to sincerely apologize for the inconvenience you have experienced due to, Problem signing in to Microsoft 365.
Since we belong to Microsoft Community site, our forum is available for public. Also, we have limited resource and privilege to examine account related scenarios.
Microsoft's back-end support team should collect more advanced log information from Office 365 Global Admin personnel through a remote session to diagnose the current scenario. If needed, a front-line technical support engineer can also have a specific support team investigate and provide you required information.
Contact our support by raising a support ticket with your global administrator account, or if you're not the administrator, you must contact your Office 365 global administrator to open the Get support - Microsoft 365 admin | Microsoft Learn (online option).
If there is anything we can assist you or if you have any further concerns, please do not hesitate to reach out to us. Your satisfaction is our top priority, and we are here to support you in any way we can.
Once again, we apologize for any inconvenience this may have caused and appreciate your understanding and patience.
Your kind understanding is greatly appreciated.
Sincerely,
Shajia Afrin | Community Moderator