Intel AMT includes a security mechanism to prevent brute force attacks that are trying to “crack” the Digest admin password. If a brute force attack is detected, connection to the device is blocked and error messages like these are recorded in the log file:
Intel(R) AMT connection error 0xc000521d: The caller is unauthorized.
After connection to the device is blocked, this error will continue to occur even when trying to connect with the correct password.
Solution:
Wait for approximately one hour and then try the requested operation again.