Are you using the ThingWorx Studio Developer portal password or the welcome email password for the Experience server?
I just tested on 1.9.1 (0.1.13.1148) and it works fine for me.
Could you please enter the credentials used on ThingWorx Studio – Unleash your imagination. and see if you still face any issue.
Also, could you please try to update your password on ThingWorx Studio site and try again. Please avoid copy-pasting the password as it may contain white space characters too.
Am using the welcome email password for the Experience server provided by the PTC pilot team. Still am getting the same error.
Santosh, this might be due to file structure not being updated. Please try stopping the Studio app, navigate to the Project location, delete all the directories and files EXCEPT src, css, extensions and app.config files. restart the Studio application. Now try publishing the project.