I was getting "Solver failed" messages last night. Using "--no-verify --no-plots --no-fits2fits --resort --downsample 2 -O" which I think has worked for me in the past. (I am using the Offline solver)

Do I need to have "Solver: Enabled" selected in the INDI Control panel > camera_being_used > Astrometry section? I would test it now but it's the middle of the day.

2016-11-22T18:25:48.275 - DEBG - Alignment: "Capturing image..."
2016-11-22T18:25:48.276 - DEBG - SX CCD LodeStar : "Upload settings set to client only. "
2016-11-22T18:25:52.420 - DEBG - fits MIN: 862 - fits MAX: 65535 - pixel range: 64673 - bin width 196.574 bin count 330
2016-11-22T18:25:52.423 - DEBG - FITHistogram: JMIndex 0.999606
2016-11-22T18:25:52.444 - DEBG - Alignment: "Image received."
2016-11-22T18:25:52.452 - DEBG - Alignment: "Starting solver..."
2016-11-22T18:25:52.612 - DEBG - Alignment: "Solver failed. Try again."
2016-11-22T18:25:52.614 - DEBG - WARNING: Phonon::createPath: Cannot connect Phonon::MediaObject ( no objectName ) to Phonon::AudioOutput ( no objectName ).
2016-11-22T18:26:09.941 - DEBG - Alignment: "Capturing image..."
2016-11-22T18:26:14.073 - DEBG - fits MIN: 855 - fits MAX: 65535 - pixel range: 64680 - bin width 196.596 bin count 330
2016-11-22T18:26:14.076 - DEBG - FITHistogram: JMIndex 0.999615
2016-11-22T18:26:14.094 - DEBG - Alignment: "Image received."
2016-11-22T18:26:14.097 - DEBG - Alignment: "Starting solver..."
2016-11-22T18:26:14.136 - DEBG - Alignment: "Solver failed. Try again."
2016-11-22T18:26:14.137 - DEBG - WARNING: Phonon::createPath: Cannot connect Phonon::MediaObject ( no objectName ) to Phonon::AudioOutput ( no objectName ).

Turn on verbose astrometry log in Configure KStars --> Ekos --> Modules --> Astrometry.net, this would display complete log of astrometry.net and will display why it failed

Okay, I just enabled it. I'll be able to try alignment again tonight. Thank you.

With the debug option set correctly, I can now see that one of my solve-field flags had a typo. Now everything is working like it should. Thank you for pointing me in the right direction!