Issue Summary:

Using a Forge automation:actionProvider: on a Custom Domain throws the error

Uncaught Error while sending bridge message: Message received from invalid origin: https://your.custom.domain.com/
Uncaught (in promise) Error: Failed to establish ready state with product

This does not happen on the non-Custom Domain for the same app.

Steps to Reproduce

1. Create a Forge app with UI Kit based on the details in Action
2. Go to Jira → COG → System → Global Automation
3. Click Create a rule → Create from Scratch
4. Add the first item, here Work Item Created → Next
5. Then: Add an action
6. Scroll to Other apps and add your Forge app
7. Click the blue connect button

Expected Results

The app connects and works the same as an atlassian.net domain.

Actual Results

The app fails to connect with the spinner always loading.

And the error in the Browser Developer Console

Uncaught Error while sending bridge message: Message received from invalid origin: https://your.custom.domain.com/
Uncaught (in promise) Error: Failed to establish ready state with product

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available