I'm trying to develop my private power up to automate some of the tedious stuff on my board. I'm currently trying to add simple card button that prepends some text to my card name. The problem starts when I execute Trello.put. The error is:
"PluginRunner::NotHandled: attempt to run callback on plugin <my API key> (<my Power Up name>) failed"
From what I could find on the internet it seems that my Power Up is missing callback capability that is supposed to be enabled in administration portal. Unfortunately I cannot see anything like that in the portal. Does callback capability still exist? How do I enable it?
