Issue
When Tableau Server has been configured for SAML authentication and the username in SAML response contains non-English characters, users cannot sign in to Tableau Server.
The following SAML errors are logged in \vizportal\vizportal-<n>.log
ERROR com.tableausoftware.samlauthentication.model.XPathUtils - Failed to evaluate XPATH in the provided input
org.xml.sax.SAXParseException: Invalid byte 1 of 1-byte UTF-8 sequence.
or
org.xml.sax.SAXParseException: Invalid byte 2 of 3-byte UTF-8 sequence.