When you try to connect to Oracle from Tableau Desktop on a Mac, the following error might occur:
An error occurred while communicating with the Oracle Database data source '<data source name>'.
Oracle database error 21561: ORA-21561: OID generation failed
Unable to connect to the server "<server name>". Check that the server is running and that you have access privileges to the requested database.
The local computer name and the name associated with the 127.0.0.1 IP address are not the same.
Edit the hosts file on the Mac to include local computer name by adding the computer name to the end of the 127.0.0.1 line. For example, the last line of the hosts file would read:
127.0.0.1 localhost <local computer name>
For more information, see How to edit your Mac's Hosts file... on iMore.
As an alternative workaround, ensure that no security software or antivirus is interfering with Tableau Desktop or Oracle.
Oracle DBA Blog: Oracle ORA-21561 : OID generation failed
Sourceforge.net: ORA-21561: OID generation failed
Oracle Support Docs: Connection Via Oracle Net Fails With Error ORA-21561: OID Generation Failed (Doc ID 559981.1)
001474048

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.