trying to run a 'Traffic' ad to a Facebook Messenger bot. In order to initiate the bot conversation I need to use the 'Get Started' button as part of the messenger ad conversation and therefore need to use the "Structured Message (JSON)" option. I cannot submit the ad since it always fails with this error
"Invalid Page Welcome Message for Messenger Destination Ads: The Message Text (page_welcome_message) is invalid for ads with Messenger as destination."
It's unclear what "page_welcome_message" is and where to set it.
I tried researching the FB community and tried to reach out but to no avail - although I did find other people with the same issue.