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NinjaOne Backup — Error 315: NAS Authentication Failed

Audience: T1 / T2 Use when: Backup fails with "Error 315: Credentials failed when authenticating to Network Storage device."

What This Error Means

Lockhart reached the NAS (network connectivity is fine) but the NAS rejected the authentication attempt. The credentials stored in NinjaOne's backup storage location don't match what the NAS currently requires.

Most Common Causes

Cause Signal
dtcbackup password was changed on the NAS but not updated in NinjaOne Error started after a NAS password rotation
dtcbackup account was deleted or disabled on the NAS Account doesn't appear in NAS user list
NAS was factory reset — cleared all local accounts All NAS settings reset
NAS was replaced with a new unit New NAS, no dtcbackup account created yet
SMB authentication negotiation failure (version mismatch) Connectivity works but auth fails even with correct credentials

Step 1 — Test Authentication Manually

# Try to map the share with dtcbackup credentials
# Replace with actual NAS hostname and the dtcbackup password from IT Glue
net use \\NAS-HOSTNAME\backups\ninjaone /user:dtcbackup [password]

# If "Access denied": credentials are wrong or account is locked/deleted
# If "Network path not found": connectivity issue (different problem — see Error 316)
# If it works: credentials are fine — the issue is with how NinjaOne stored them

Step 2 — Verify dtcbackup Account on the NAS

Synology DSM:

  1. Control Panel → User & Group → Users tab
  2. Find dtcbackup — confirm it exists, is not disabled, and is not expired
  3. Check the account's share permissions: it should have Read/Write on backups

QNAP QTS:

  1. Control Panel → Privilege → Users
  2. Find dtcbackup — confirm active
  3. Check Shared Folder Permissions for backups — should be Read/Write

Step 3 — Update Credentials in NinjaOne

If the password was changed on the NAS or a new NAS was set up:

  1. NinjaOne → Administration → Organizations → select the client org
  2. Org settings → Backup → Storage Locations
  3. Click the storage location → Edit
  4. Update the Username and Password fields with the current dtcbackup credentials
  5. Save
  6. Trigger a manual backup run

Step 4 — Recreate the dtcbackup Account (If Deleted)

If the account was removed:

Synology:

  1. Control Panel → User & Group → Create
  2. Username: dtcbackup, password per DTC credential standard
  3. Do NOT add to the administrators group
  4. Shared Folder Permissions: Read/Write on backups only
  5. Update NinjaOne storage location credentials (Step 3)

QNAP:

  1. Control Panel → Privilege → Users → Create
  2. Same naming and permission structure

Step 5 — SMB Version Check (If Credentials Are Correct But Auth Still Fails)

If credentials are verified correct but Error 315 persists, the issue may be SMB authentication negotiation:

# Check SMB negotiation with NAS
Get-SmbConnection | Where-Object {$_.ServerName -like "*NAS*"} | Select ServerName, Dialect, UserName

# If Dialect is 1.0 on a Windows Server 2016+ device: SMBv1 authentication behavior may differ
Get-SmbServerConfiguration | Select EnableSMB1Protocol, EnableSMB2Protocol

Update NAS firmware to support SMBv2/v3 if SMBv1 mismatch is the cause.

If net use returns "System error 86 — the specified network password is not correct" (not Access Denied), the password is verified correct, and the same credential works from another machine: this is an NTLM auth-level (LmCompatibilityLevel) problem on the affected server, not an SMB dialect issue and not a NinjaOne credential issue. See NinjaOne Backup — SMB Credentials Rejected (System Error 86): LmCompatibilityLevel / NTLMv2.

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