Windows System Errors
RPC Server Unavailable
0x800706BAReviewed for reference consistency: August 11, 2026
the remote procedure endpoint could not be reached
What 0x800706BA Means
The 0x800706BA error on the Windows System Errors indicates rpc server unavailable — the remote procedure endpoint could not be reached. This typically occurs due to the rpcss service or the target service is not running on the destination machine.
0x800706BA is Win32 error 1722, RPC_S_SERVER_UNAVAILABLE: the remote call never reached a listening server. The system message reads 'The RPC server is unavailable', and management tooling that leans on DCOM and WMI makes the code a common cross-machine diagnostic: the local caller works, the remote endpoint does not answer.
How to fix 0x800706BA
General informational guidance, not professional advice. Commands can affect your system or data — back up first and proceed at your own risk. FixerCode is an independent reference, not affiliated with any vendor mentioned.
Probe the endpoint mapper port
A TCP probe to port 135 shows whether the RPC infrastructure at the destination is reachable at all.
Test-NetConnection <target-host> -Port 135Verify the WMI repository locally
WMI-backed tooling depends on a consistent repository; the verify switch reads its state without changing it.
winmgmt /verifyrepository
Technical Background
Two rendezvous stages can fail, and they look identical from the caller. The endpoint mapper on port 135 hands out the port for the requested interface; if that stage is unreachable the call never starts, and if the negotiated dynamic port is blocked the call dies immediately after. Distinguishing the stages requires port-level probing rather than repeating the same failing call.
The code also appears in single-machine contexts when a service hosting an RPC interface is stopped or crashed. In that case there is no network story at all — the local RPC infrastructure reports the absence of the server that should be listening. Service state and event-log entries for the target service resolve the local variant quickly.
Microsoft's Active Directory guidance frames 1722 as a lower-layer connectivity failure mapped into RPC: the TCP CONNECT itself failed. The documented cause list sets the diagnostic order — name resolution first, then routing and firewall policy on the mapper port and the ports behind it, then the service that should be listening.
Common Causes
- The RPCSS service or the target service is not running on the destination machine
- Firewall rules block the endpoint mapper port or the dynamic ports behind it
- Name resolution or routing sends the call to a machine that cannot answer
- A higher-layer protocol that is not running, or that returns this error itself
Typical Scenarios
- A WMI or CIM query against a remote server fails with 1722 while the same query succeeds locally
- A domain-joined machine cannot reach a domain controller's RPC endpoints during authentication or replication checks
- Firewall policy allows the endpoint mapper but blocks the dynamic ports negotiated behind it
- repadmin or dcdiag replication checks fail with 1722 (0x6ba) against a domain controller
What to Know
A port probe to 135 and then to the negotiated endpoint splits the failure into mapper-reachability versus dynamic-port policy, which are different fixes on different machines.
Frequently Asked Questions
Common questions about Windows 0x800706BA error
It is the service process hosting the called interface, not a distinct server product. The constant fires when nothing at the destination answers for that interface.
Different tools call different interfaces, and each interface negotiates its own endpoint. A policy or service failure can block one interface while leaving the mapper and other interfaces reachable.
1722 (RPC_S_SERVER_UNAVAILABLE) is the rendezvous failing — no server reached. 1726 (RPC_S_CALL_FAILED) marks a delivered call whose server-side execution failed.
Within Active Directory replication, 1722 is the visible end of a lower-layer failure: most often the underlying TCP CONNECT never completed. DNS lookup failures account for a large number of replication 1722s, so name resolution gets checked before ports.
The 0x8007 prefix marks a Win32 error wrapped in an HRESULT, so the payload 0x6BA is plain error 1722, RPC_S_SERVER_UNAVAILABLE — the same code tools such as repadmin print as 1722 (0x6ba).
Yes. Port 135 hands out the endpoint, but the service listens on a separately assigned port; if policy blocks that one, the mapper stage passes and the call dies anyway. Splitting the stages takes a probe of each port.
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