"No longer in business (and website is now parked with gambling ads)"
The place has gone or never existed. A user of Organic Maps application has reported that the POI was visible on the map (see snapshot date below), but was not found on the ground.
OSM snapshot date: 2023-12-13T18:30:01Z
POI name: Velká klášterní restaurace
POI types: internet_access-wlan amenity-restaurant
 #organicmaps android