We are using a custom Google Chrome extension to add some custom buttons under the “ADD TO CARD” section on the right of an open card.
These custom buttons opens a modal and adds some functionality that interacts via an API with our internal time/project management functionality.
Late last week and early this week users users are unable to view the modal that opens after clicking a custom button. It just loads the loader gif.
In the Chrome console, it shows the following:
Access to XMLHttpRequest at 'https://abc.xyz.com/task_item?_=1586663570296' from origin 'https://trello.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The 'Access-Control-Allow-Origin' header has a value 'null' that is not equal to the supplied origin.
Please advise on what has changed recently and if we can correct this on our custom Chrome extension?