Can't share a folder on a local network in Microsoft Windows Server 2025 STD

Because both servers are domain joined, repeated credential prompts indicate authentication, name resolution, or permissions failure; guest access or SMB1 is not the fix. From the client, connect with the server’s real DNS name, not its IP address, and confirm TCP 445 is reachable. Verify both servers use Active Directory DNS and have synchronized time. Clear only existing connections to that server, then retry with an explicit domain account. Confirm both share and NTFS permissions grant the same domain user or group access. Review the SMB Client and SMB Server event logs for the exact failure. Windows Server 2025 requires SMB signing by default and blocks guest fallback, so do not disable those protections merely to remove the prompt. If a DNS alias is required, register it as an alternate computer name with the correct SPNs. The resulting event code will distinguish Kerberos, credential, firewall, and authorization failures.