Earlier in the week, there was a notification system implemented to the platform for failed calls - this would send data from the backend to the front end for call status notifications.
There was an account making a very large volume of calls with no balance at the account level which was sending notifications to the frontend which slowed it down.
There have been changes made to ensure this doesn't happen with re-works scheduled over the weekend to better handle situations like this and call rate limits have temporarily decreased to cool the server memory.