2. Check the configuration file: Check whether the configuration file of nohbase correctly sets the address and port of the master node.

3. Confirm that the master node is running normally and accessible.

4. Check the network connection: confirm that the network connection between the server where the master node is located and other nodes is normal.

5. Restart nohbase service: None of the above methods can solve the problem. You can restart the nohbase service to ensure that all configurations and modifications take effect.