Why is my authentication failing with internal_server_error when using Plum?

Some Plum users that still use Plum's Facebook Messenger chatbot might see the error below after successfully authenticating with the bank.

{
"error_description":"Sorry, we are experiencing technical difficulties. Please try again later.",
"error":"internal_server_error",
"error_details":{}
}

Facebook Messenger sometimes fails to set the browser cookies to ensure the process is finished. When this happens,  the error above is triggered.

Solution 

What to do next?

Plum now provides native iOS and Android apps. Please install them to make sure the authentication flow goes smoothly.