** UPDATE 08/06/2021 14:05 EEST **
Issue should be resolved now and your queries should run normally. Once again apologies for this trouble and thank you for your patience!
There is currently an issue with Facebook Ads queries causing them to fail. We are investigating the cause for this with highest priority.
We'll update this article as soon as there is any new information to share. Our apologies for any inconvenience caused by this.