I have recently started using Houdini again (such an awesome program!) and have been using for a few weeks.

I tried to start it again today and it wanted to re-install the license key but I am getting an error and unable to open the program.

“Error parsing JSON response from the web server. Invalid JSON:”

Along with some HTML code.

How can I solve this issue?

Cheers
David

When installing Apprentice, you don't need the license server so choose the other option.

When I get license failures I do an uninstall and re-install.

I indeed jumped the gun! A simple re-install of H15 fixed the problem.