unavailable Authenticator

Hi @VENKATESWARLU M

I'm just another user here on this public forum, not your organization's admin, so I'm not able to reset or unlock anything on your account myself.

Because you are the only administrator and you've been locked out of the account, you'll need to contact Microsoft's Data Protection team for assistance. They are the only team authorized to help recover access in situations involving the sole administrator account. 

When a call is made to support, the first step is to provide an automated voice response from AI. Be careful, you won't be able to speak to a support representative if you don't respond appropriately here. 

Contact Microsoft customer support | Microsoft Support 

Here's an example of a response that actually led to a support representative. Please refer to it. 

Q. Can you tell me if you are calling as a home user who uses a product or service at home or a business user who uses it in your business to provide the best assistance? 
A.I am a business user. 
Q. Thank you. Can you give me the details of your inquiry? 
A. Login technical support. 
Q. First of all, can you tell me which products you are inquiring about today? 
A. Microsoft 365 business Standard。 
Q. Please wait a moment, I understand Microsoft 365. Are you calling about a new case or an existing one? 
A. New. 
Q. To receive phone support, your phone number must be associated with your Microsoft 365 admin profile. To do this, go to aka.ms/m365profile. Again, it aka.ms/m365profile . This can take 48 hours. In the meantime, you can go to aka.ms/m365profile and file a case online. If you prefer, you can also text the link to the phone number you are calling. What do you think? 
A. The phone number is already linked to the link. 
Q. Can you tell me about the products in your inquiry? 
A. Microsoft 365 Business Standard. 
Q. Are you a Global Administrator? 
A. That's right. 
Q. I'm sorry. I didn't understand. Are you a global administrator for your domain? 
A. Yes, I am a global administrator for the domain. 
Q. If you have any inquiries, you can contact a Microsoft representative. Are you sure? 
A. Yes. Please. 
Q. Yes, I understand. Please wait a moment.

Please note that this team is always overwhelmed, so you might need to wait for them to call you, this should take 3-10 working days.

In case the phone line is not supportive, you can consider directly submitting a support request as a helpful workaround:    

Consider signing up for a trial subscription to create a new tenant. Visit Microsoft 365 Business Plans and Pricing | Microsoft 365. 

Once the new tenant is set up, you can access its admin center and submit a support ticket through Microsoft 365 admin center > Support > Help & Support to contact the Data Protection team regarding the previous tenant. Please remember to cancel the trial subscription after your issue is resolved, as this will help you avoid any accidental billing. You may prefer the following resource for detailed instructions: Cancel your Microsoft business subscription in the Microsoft 365 admin center | Microsoft Learn 

I hope this helps point you in the right direction. If you have any updates or additional questions, feel free to reply back and I'll do my best to assist further.