I´m triying to create a Zapier's custom activity within Journey Builder, but I´m having problems to show it in SFMC, pulling me the followin error: "One or more custom activities failed to load. Verify that custom activity endpoints are valid and refresh the Interaction."
I have checked the information within APP center, and it seems to be right. Within Heroku, the app is well deployed, but I cannot view it after deploying. I believe that the error comes from the package within Github, but after investing weeks, I cannot find the problem why the app is not running.
If anyone can help me, I would be very grateful because that problem drives me crazy :)
Thanks in advance!