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= Error Messages =
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== Error and warning dialogs ==

=== Unknown host === #UnknownHost
When you download data from or upload data to the OSM server JOSM tries to establish a connection with the OSM server. If it can't resolve the host name of the OSM server, it displays the following error message:

[[Image(unknown-host.png)]]

'''How to resolve'''
 * check the URL displayed in the dialog (in the example above it's {{{http://nosuchhost.openstreetmap.org/api}}})
 * make sure your [wiki:/Help/Preferences] include a valid URL to the OSM server. The standard URL is {{{http://api.openstreetmap.org/api}}}