I would unplug the battery for a few, rinse the probe with distilled, and rinse whatever sample cup I'm using for calibration. Then give it another try.
Also, I see your thermometer probe is in there. I suppose its possible its creating some trace current that could screw up your reading. Measure your temp and remove the temp probe, then use your ph probe and calibrate
Temp is important but keep in mind the accuracy of your meter, +/- .01. That's equal to about 5 degrees C difference. So you could know precisely what your temp is but your meter makes that level of precision irrelevant. Then for our purposes, really +/- .1 is not horrible.