Encountered an error message "Failed to create a persistent connection to ADMIN$" when try to add managed server become a proxy. Particular Proxy is a stand-alone and not join to the domain.
Product:- Veeam Backup & Replication
[Resolution]
Try to disable UAC from registry
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System.
Create a DWORD value called LocalAccountTokenFilterPolicy and assign it a value of 1.