How do I troubleshoot the 'No server is available to process the request' error in NCache?

Ensure that the NCache Server port is not blocked by the firewall. The default Server port is 9800 and is used by the NCache Service to accept client connections.

How do I resolve the 'Unable to communicate with server node' error in NCache?

Ensure that the cluster ports required by the configured caches are allowed through the firewall so that nodes in the cache cluster can communicate.

What should I do when the NCache Management Center cannot connect to the NCache Service?

Ensure that the system firewall allows traffic on the NCache Management Port, which is port 8250 by default.

What should I do if an existing clustered cache is not visible in the NCache Management Center?

Open Clustered Caches in the NCache Management Center, click Add, specify the IP address of a server node where the cache is registered, select the required cache from the detected caches, and click Finish.

Troubleshooting

Sometimes a cluster cannot be formed, or cluster nodes are unable to communicate with each other. It may happen when Server and Cluster ports are blocked by a firewall. The following error messages can occur in this case:

Server Communication Error

Error: "No server is available to process the request"

Error: "Unable to communicate with server node"

Error: "The NCache Management Center is unable to connect with the NCache Service"

Note

Check your firewall settings using the details in the NCache Install Guide.

Workaround

For the error, No server is available to process the request, make sure that the Server port (at which the NCache Service starts and accepts different client connections) is not blocked by a firewall. The default value of this port is 9800. You can change the default value from the cache server configuration file found in NCache as follows:
- Windows: Alachisoft.NCache.Service.exe.config located in %NCHOME%\bin\service
- Linux: Alachisoft.NCache.Daemon.dll.config located in /opt/ncache/bin/service
For the error, Unable to communicate with server node, check to see that the cluster port is permitted by your firewall. A cluster port is a port at which nodes in a cluster communicate. You can change the default value of these ports from the NCache Management Center. Ensure that the cluster ports required by your configured caches are allowed through the firewall.
For the error, The NCache Management Center is unable to connect with the NCache Service, ensure that the system firewall allows traffic on the NCache Management Port, which is 8250 by default.

Cache Not Visible in NCache Management Center

Sometimes a clustered cache may already exist on a server but does not appear in the NCache Management Center.

Workaround

If the cache already exists and is running on a server node, add it to the NCache Management Center without recreating it:

Launch the NCache Management Center by browsing to http://localhost:8251 or <server-ip>:8251.
In the left navigation bar, click on Clustered Caches or Local Caches, based on the cache for which you need to configure the settings. The page shows any existing clustered caches on your machine and additional details like Topology, Servers, and Server Platform.
To add a registered clustered cache, click on Add.