If an image is pulled onto the map the coordinates for longitude and latitude are filled in automatically. The context menu contains the option "Look up of missing altitude values" which used to work in the past, but now (tested with 4.4.0 and 4.6.0) just returns with no visible change.

From the console I figured out that the plugin for example tries to open the URL http://ws.geonames.org/srtm3?lats=36.2432970827&lngs=-116.817792886
That fails if you do it in a browser with the message "ERR:10:Please add a username to each call in order for geonames to be able to identify the calling application and count the credits usage." which seems also to be the solution to the error.

Reproducible: Always