Extrusion problem

Hello, i have a problem with manual extrusion in repetier host - i press the "extrude" button and nothing happens - and f i start printing it works - not so good, but i have another topic for that.
What can be the problem?
if i push it with hands it also works.
The Retract also doesnt work
I work with PLA, 210 degrees. it worked in the beginning but now doesnt, and it doesnt write anything in the Log about it.
Thank you

There's a few things... does the motor spin without filament inside of it? is the extruder motor hot?

Assuming that the motor isn't the issue, have you tried to verify the temperature with a separate temperature reading device?

It's very easy for something to say one temperature and the actual filament be experiencing a different temperature all together.
PLA is especially problematic if temperature is a problem. I've had PLA gum up my extruder by being extruded too cold, but I've read of problems with it being too hot as well.

Just based on what you've said thus far, I'm inclined to think that the thermistor isn't reading true and your filament isn't actually at the right temperature. Seal up the thermistor so it doesn't leak heat, and try to verify the temperature with an outside thermometer (like a fancy non-contact one).

Is the hotend at extrusion temperature when you try to extrude manually? If PREVENT_DANGEROUS_EXTRUDE is set in your firmware, the extruder motor won't run if it isn't.