There is currently an active issue with TabPy Server connecting to Tableau Server versions 2018.1 and up. An error is occurring in the default timeout value for communications with TabPy.
We now have a workaround for the issue: By manually setting this value in the server configuration using Tabadmin we can allow for connections to operate normally. The command to set is <vizqlserver.extsvc.connect_timeout_ms> and the default value to set it to is 1000. If setting this value to 1000 ms causes a timeout error, experiment with extending the timeout time. For more documentation on setting values with Tabadmin refer here: