APC Disk On-line Server NAS-2100 - Manual (Page 105)

3. When the following message appears after applying the settings in step 2,
check the DNS IP.
When the following message appears after applying the settings in step 2,
domain name, domain user name, and the password.
When the following message appears after applying the settings in step 2,
check the time zone settings. Make sure the difference of your time and that
of AD server is less than 5 minutes. If the time difference is larger than 5
minutes, you will not be able to add the domain member.
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