I am using the Simulators and the Offline solver.
Everything worked beautifully until I clicked on Restore Defaults in the Options. After this all my trials failed .
I reinstalled KStars and follow the instruction to install the astrometry.net feature (they were already checked in the Wizard).
I get this message : 2017-07-19T18:15:36 Solver failed. Try again.
2017-07-19T18:15:36 This program is part of the Astrometry.net suite.
For details, visit astrometry.net.
Git URL github.com/dstndstn/astrometry.net
Revision 0.70, date Wed_Dec_7_11:52:34_2016_-0500.