As an existing user (username: madasha) I am attempting to approve a claimed talk from the following event: https://joind.in/event/bulgaria-php-2016
The talk URL: https://joind.in/event/bulgaria-php-2016/scaling-php
I go to https://joind.in/event/bulgaria-php-2016/claims, click on the [Approve] button, and I get a 500 ISE error ("We're sorry, but an error occurred.").
Here's the cURL POST request representing the form submission:
Here's the response headers:
Additional info: Using Firefox 53.0 under Ubuntu. Have in mind that the event took place relatively long time ago (Oct 2016) and I've forgotten to approve that talk then.