I have exactly the same error/issue - struggling to debug it to be honest as I also have the [OK] message between Sparkler and Tableau and the logs are less than informative.
Double-check your user parameters in Sparkler.xml, and make sure you set up your Sparkler IP addresses as trusted ticket sources on Tableau Server per Task 6 on page 18. If you didn't do Task 6 it'll give you that error despite an OK on the status screen.
We faced the same error "Invalid trusted ticket. ticket=-1" while opening Tableau workbook on SFDC.
We have SSL configured on Tableau server apart from Sparkler. There is also a Load balancer.
Tableau SSL certificate was added to Java trusted certificate store (CACERTS) on Sparkler server, but the issue remained.
After analyzing, httpd error logs from Tableau server we found that X-Forwarded-For header was not enabled on load balancer and therefore to tableau all requests seem to be coming from the same IP and because of it trusted authentication failed.
We enabled X-Forwarded-For HTTP header on Load balancer to resolve the error.
Note: Adding Load balancer IP address to the trusted hosts list on Tableau server might also solve the issue but that has security risk. So we may try this step as temporary workaround till the issue is solved.
Hope this helps.