Power Platform Community Forum Thread Details

I have an automated cloud flow using the Microsoft Teams "When a transcript
is available" trigger (scope: Ad-hoc call for a user). The trigger fails to
register its webhook subscription. Every activation returns:

HTTP 400 / InvalidInput
"NotificationUrl must use the https scheme. (Parameter 'input')"
trigger type: OpenApiConnectionWebhook

Because of this the flow has never triggered (Flow checker shows "not
triggered successfully in the last 28 days").

What I've already tried:
- Deleted and re-added the trigger several times (which regenerates the
callback URL)
- Re-saved the flow
- Confirmed the connection is valid

The error returns every single time. Since recreating the trigger regenerates
the NotificationUrl and it's still rejected, this looks like the
platform-generated callback URL is malformed at the environment level rather
than a flow-config issue. The flow is in the Default environment. I'm
wondering if it's related to the HTTP/Teams webhook URL infrastructure
migration (MC1168342).

Questions:
1. Has anyone resolved this specific error for the Teams call/transcript
triggers?
2. Is this an environment/region provisioning issue?
3. Is the fix a support ticket, moving environments, or something I can
change myself?

Thanks!