Ad inserter settings blank, no blocks to choose from, can’t us code window

Hi

I just tried using ad inserter for the first time, but my settings window is missing some key elements like the blocks selection. I also can’t click the code window or enter anything.

When loading the page, example code is briefly visible, but vanishes when the page is finished loading.

I have disabled ublock and even added an exception to the online threat prevention of my antivirus. I have also tried a different browser without adblock even installed – nada.