Typically, troubleshooting involves a number of steps that are rather consistent regardless of the particular situation. These steps include the following:
Verify that YugabyteDB is running: you need to ensure that the expected YugabyteDB processes are running on the current node. At a minimum, the YB-TServer process must be running to be able to connect to the node with a client or application.
Additionally, depending on the setup, you might expect a YB-Master process to run on this node.
For more information, see Check processes.
Check cluster-level issues and their solutions.
Check logs: you should inspect the YugabyteDB logs for additional details on your issue. For more information, see Inspect logs.
Explore knowledge base articles: you can find additional troubleshooting resources and information on Yugabyte Support page.
File an issue: if you can't find a solution to your problem, file a GitHub issue describing your specific problem.