Reason for reducing site authority domain?

[5mizo]

Hi;
I have a website that had an authoritative domain of 10 but today it has reached 5. I wanted to know what the reason for these changes was.
No backlinks from my site have disappeared and even more, but today my authoritative domain has reached 5 authoritative domain.
Can you guide my servant?

My website to troubleshoot  :   bonianservice.com

Thank you very much

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[herrmans]

There are a number of reasons why this problem can occur, the main reason being the drop in the number of domains from which you have received backlinks.
I also encountered this problem on https://archina.ir