Why doesn't fancybox work on a link in a Yandex map?

Question

JavaScript

Could you tell me why fancybox does not work on the site when you click the link in Yandex maps ?
it works on the page itself, but in the maps if you click on the link from the balloon - silence and there are no errors in the console.
tell me where to dig with a sapper's shovel?

Answer 1

How are there no errors, if any?)

template_d346d4d32143e959c59734b619518ebf_v1.js?1601534782598478:388 Uncaught TypeError: Cannot read property 'add' of null