Error "The issuer certificate... could not be found" Signing into Tableau Online or Tableau Server via Tableau Desktop Using SAML

Issue

When signing into Tableau Online or Tableau Server from Tableau Desktop on a Mac using SAML, the following error might occur:

Cannot connect to Tableau Server. Please check the server name and port and try again.
The issuer certificate of a locally looked up certificate could not be found
No certificates could be verified

Environment

Tableau Online
Tableau Server
Tableau Desktop on Mac
SAML

Resolution

The SAML Identity Provider (IdP) needs to send the whole certificate chain, up to but not including, the root certificate.

Work with your internal IT team to configure the IdP responses to include the full certificate chain. When the full certificate chain is made available during the authentication process, then the authentication will be successful, and you will be able to fully log into Tableau Online through Tableau Desktop on Mac.

Cause

Some programs will download this certificate for you, but Tableau on Mac, or more precisely, OpenSSL, does not.

Additional Information

Some programs will download this certificate for you, but Tableau, or more precisely, OpenSSL, does not. The reason this works on Windows is that WinInet downloads and stores these certificates. The Mac will download but not store the certificates, thus it will work in the browser on Mac.