@edit Through the browser developer console I was able to extract an actual error message:
Invalid AvailableAddOnSid provided
But what does that actually mean. I find nothing on the web and in fact have no Twillio Add-Ons installed.
Yesterday I successfully integrated Dialogflow and Twilio per one-click-integration.
Today I wanted to do the same with another agent but always got an unspecified error when completing the last step in twilio. See screenshot of error in popup of last step in integration:
I did not change anything. What can it be and why isn't the error more specified?
It seems that problem has already been solved by Twillio. I opened a ticket and they responded that it was an Twillio issue and should be solved now.
It's working now!