Searching via CNB - Czech National Bibliography

I have CNB - CZECH National Bibliography search set up. When I try to Add a books by ISBN or by name, it is not found. Everything was working before, but for the last few weeks the search is not working. Book search returns the error "The search has failed." The books are registered in CNB and can be found directly via CNB ( https://aleph.nkp.cz/F/?func=file&file_name=find-b&CON_LNG=ENG&local... ).
Examples of ISBN: 9788025344057, 9788025333761
Examples of book titles: "Roboti a impérium", "Nadace".

Several sources are not working. I have added this to the main report.

https://www.librarything.com/topic/343006

I think this is working now, but only for title searches.