It's likely that you have not set up Authentication properly. You can't use Windows Authentication so the first thing to try is setting Authenication to Basic.
Alternatively try this solution from this
post from VVak[
^]
Quote:
Open registry editor - regedit. And navigate to:
HKEY_LOCAL_MACHINE -> SYSTEM -> CurrentControlSet -> Control -> Lsa
Look for key "DisableLoopbackCheck" and check the value in this key. If it is 0, change it 1.
If this key does not exit, create a new key with the same name - "DisableLoopbackCheck" - and assign it the value of 1.
Restart the server. And the issue should be fixed.
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