Nozzle sensor

[tconley 0]

I am getting a new error message about a nozzle sensor not working properly.  This has never happened before and I recently upgraded to new firmware.  Could this be the problem?  I am on a U3 and U3 Extended.

[tconley 0]

actual error

"Nozzle offset probe failed"  I am running an AA 0.4 and a BB 0.8 Print core.

[Smithy 1,146]

This often happens when the tip of your nozzle is not clean or on the glass there are still small filament residues exactly where he makes the measurement.

[tconley 0]

Smithy, 

Thank you. I have cleaned the surface and the tips.  I did another manual leveling and now the machine will start to do a calibration like it wants to print but it is hovering a quarter inch above the plate.