Before reporting problems please read the user documentation and FAQ. If your problem relates to the address of a particular search result please use the 'details' link to check how the address was generated before reporting a problem.
Use Nominatim issues on github to report problems.
Please ensure that you include a full description of the problem, including the search query that you used, the problem with the result and, if the problem relates to missing data, the osm type (node, way, relation) and id of the item that is missing.
Problems that contain enough detail are likely to get looked at before ones that require significant research.
Nominatim is a search engine for OpenStreetMap data. This is the debugging interface. You may search for a name or address (forward search) or look up data by its geographic coordinate (reverse search). Each result comes with a link to a details page where you can inspect what data about the object is saved in the database and investigate how the address of the object has been computed.
For more information visit the Nominatim wiki page.