It seems the Czech National Archives stopped using that domain. All the data should be now in the database at https://vademecum.nacr.cz/
Or you can check the archives menu at https://www.nacr.cz/en/for-public/research-room/digital-research-room-archival-records-on-line 
Unfortunately it seems the new URLs are constructed differently so it is not possible to use the paths from the old links to access the specific scans or images.

Dana Polakovicova
Czechia / Slovakia

What happened to the Badatelna images that used to be on their site? Does anyone know where they can be accessed now?
For example, I had recorded this link that no longer works:  http://www.badatelna.eu/fond/1073/reprodukce/?zaznamId=2860&reproId=43379  
Thanks for your help,
Larry Bassist
USA