Bobcares

The RPC server is unavailable – How to resolve

by | May 6, 2021

Wondering how to resolve ‘The RPC server is unavailable’ error? We will help you with that.

The error appears on Windows when a communication error occurs between two computers in a network.

The computer (an RPC client) cannot connect to a remote computer (an RPC server). So, the program we are running does not work and returns an RPC error because it cannot access data on the remote host.

As a part of our Server Management Services, our Support Engineers helps to fix similar errors regularly.

Today let us discuss some common causes for this error and how our Support Engineers tackle them.

Causes for ‘The RPC server is unavailable’ error

 

Usually, If an RPC client was unable to connect to an RPC server, the following error appears in the app:

Modern Windows versions use the Dynamic RPC Port range from 49152 to 65535. Windows Servers used a different RPC port range from 1024 to 65535.

Today, let us see some of the causes for the error:

1. Firstly, a remote computer is turned off.
2. Secondly, RPC services are not running on the remote host.
3. Next, We are trying to connect to an RPC server using the wrong hostname (or a wrong IP address matches the server DNS name).
4. Next, Incorrect network connection settings are used on the server or client.
5. Finally, RPC traffic between client and server is blocked by the firewall.

 

Solution for ‘The RPC server is unavailable’ error

 

Today, let us see steps that Support Techs follow in order to fix the error.

  • Checking Remote Computer Availability

Firstly, make sure that the remote computer is turned on. We can use ping command. We should try ping command by its name and IP address.

If the RPC server is not available by the hostname, check if DNS records are correct and try to flush the DNS cache on the client:

ipconfig /flushdns

If the name of the computer our RPC server is running on has been changed recently, try to re-register it in Active Directory DNS:

ipconfig /registerdns

 

  • Check the Status of DCE/RPC Services

Next, make sure that the services processing incoming RPC connections are running on the server:

1. Firstly, open the Service Management console (services.msc).
2. Then, make sure that the following services are running and configured to start automatically:

  • Firstly, remote Procedure Call (RPC)
  • Secondly, RPC Endpoint Mapper
  • Finally, DCOM Server Process Launcher

We can check the status of the services via PowerShell:
Get-Service RpcSs,RpcEptMapper,DcomLaunch| Select DisplayName,Status,StartType

If RPC services are stopped and we cannot start them, try to activate them through the registry. Find the registry key of the services and change the value of the Start parameter to 2 (automatic service startup):

  • Remote Procedure Call (RPC) — HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RpcSs
  • RPC Endpoint Mapper — HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RpcEptMapper
  • DCOM Server Process Launcher — HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\DcomLaunch

 

  • Firewall is Blocking RPC Connections

In this case, make sure that the RPC traffic between computers is not blocked by the firewall. If we are using Windows Defender Firewall with Advanced Security, we need to create the rules allowing RPC traffic or make sure that they exist.

Generally, one of the rules is to allow access to the RPC Endpoint Mapper service over port TCP 135. Another one is to allow access to the RPC service we want to use through the RPC Dynamic Ports. Create the rules for all network profiles: Domain, Private and Public.

We can create the rules manually. In an AD domain environment, we can deploy firewall rules using GPO or use PowerShell scripts.

Make sure that port TCP/135 is available on our RPC server from a client (the RPC Endpoint Mapper must listen on it). We can check the port availability via PowerShell:

Test-NetConnection 192.168.1.201 -port 135

If the RPC port is available, we will see the message:

TcpTestSucceeded:True

We can get a list of RPC endpoints (services and applications) registered on the remote computer and advertised by the RPC Endpoint Mapper service using the PortQry tool:

portqry -n 192.168.1.201 -p tcp -e 135

In the PortQry output, we can see the number of the port assigned to the RPC service we want to use (is it running) and make sure that the port is not blocked from the client.

Generally, If we are using a third-party firewall/antivirus software, make sure that it does not block RPC traffic and can correctly process the RPC Dynamic Ports traffic.

 

  • Check Network Protocols & Settings

Then, make sure that the network settings on our computer are correct: the IP address, default gateway, subnet mask, DNS server settings (we can check the network settings from PowerShell).

Also, make sure that Internet Protocol Version 6 (TCP/IPv6) and File and Printer Sharing for Microsoft Networks are enabled in the settings of the network adapter.

Usually, some network apps do not work correctly if the TCP/IPv6 protocol is disabled and return the error: 1722 The RPC server is unavailable. If the RPC error persists after enabling IPv6, try to disable the Teredo protocol through the registry:

Finally, create a DWORD parameter with the name DisabledComponents and value 8 in the reg key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters:

reg add hklm\system\currentcontrolset\services\tcpip6\parameters /v DisabledComponents /t REG_DWORD /d 8

 

[Still, not able to resolve this SMTP error? We can help you in fixing it]

Conclusion

In short, this error occurs when a communication error occurs between two computers in a network. Today, we saw how our Support Engineers resolve this error message for our customers.

PREVENT YOUR SERVER FROM CRASHING!

Never again lose customers to poor server speed! Let us help you.

Our server experts will monitor & maintain your server 24/7 so that it remains lightning fast and secure.

GET STARTED

var google_conversion_label = "owonCMyG5nEQ0aD71QM";

2 Comments

  1. Joan Lolmaugh

    What is the cost of your service?

    Reply
  2. Maheen Aboobakkar

    Hello Joan,

    We’ll be happy to talk to you on chat (click on the icon at right-bottom).

    Reply

Submit a Comment

Your email address will not be published. Required fields are marked *

Never again lose customers to poor
server speed! Let us help you.

Privacy Preference Center

Necessary

Necessary cookies help make a website usable by enabling basic functions like page navigation and access to secure areas of the website. The website cannot function properly without these cookies.

PHPSESSID - Preserves user session state across page requests.

gdpr[consent_types] - Used to store user consents.

gdpr[allowed_cookies] - Used to store user allowed cookies.

PHPSESSID, gdpr[consent_types], gdpr[allowed_cookies]
PHPSESSID
WHMCSpKDlPzh2chML

Statistics

Statistic cookies help website owners to understand how visitors interact with websites by collecting and reporting information anonymously.

_ga - Preserves user session state across page requests.

_gat - Used by Google Analytics to throttle request rate

_gid - Registers a unique ID that is used to generate statistical data on how you use the website.

smartlookCookie - Used to collect user device and location information of the site visitors to improve the websites User Experience.

_ga, _gat, _gid
_ga, _gat, _gid
smartlookCookie
_clck, _clsk, CLID, ANONCHK, MR, MUID, SM

Marketing

Marketing cookies are used to track visitors across websites. The intention is to display ads that are relevant and engaging for the individual user and thereby more valuable for publishers and third party advertisers.

IDE - Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.

test_cookie - Used to check if the user's browser supports cookies.

1P_JAR - Google cookie. These cookies are used to collect website statistics and track conversion rates.

NID - Registers a unique ID that identifies a returning user's device. The ID is used for serving ads that are most relevant to the user.

DV - Google ad personalisation

_reb2bgeo - The visitor's geographical location

_reb2bloaded - Whether or not the script loaded for the visitor

_reb2bref - The referring URL for the visit

_reb2bsessionID - The visitor's RB2B session ID

_reb2buid - The visitor's RB2B user ID

IDE, test_cookie, 1P_JAR, NID, DV, NID
IDE, test_cookie
1P_JAR, NID, DV
NID
hblid
_reb2bgeo, _reb2bloaded, _reb2bref, _reb2bsessionID, _reb2buid

Security

These are essential site cookies, used by the google reCAPTCHA. These cookies use an unique identifier to verify if a visitor is human or a bot.

SID, APISID, HSID, NID, PREF
SID, APISID, HSID, NID, PREF