Up mini print halfway

Hi

i have a up mini printer. the printer prints all fine but then it

  1. starts printing in the air
  2. or sometime stops generating the filament.

And additional question,

  1. can i shutdown my computer when the printing codes have been sent to the printer and its start printing?

  2. do i need to clean the head of the printer? and how to clean ? thank you

thank you. am newbie to 3d printer.

for the second part of the questions, yes you can close the computer but in up plus2(my printer) when you close the application it never connects again until you uninitialize by hand in soda software I don’t now if up mini has similar issue, and to clean nozzle just unattach and attach filament few times until you don’t see black marks.