You can then try clearing the hotend with the following procedure:
1) Unload any filament in the printhead.
2) Set printer to Preheat and wait for the nozzle to reach at least 150C.
3) Take a needle from the Maintenance Kit and insert it a few times up into the nozzle from the bottom, taking care not to touch the hot nozzle in the process.
4) Set the printer to Load Filament and load the nylon cleaning filament from the Maintenance Kit.
5) Download the ZYYX Cleaning Script to the SD card. (See below.)
6) Run the script in the printer with the cleaning filament loaded three times. At the end of each script the printer will unload the filament, so it is best to pull out the filament and reload it in between each run of the script. (Please note that it is normal for water vapor to appear when the cleaning filament is loaded.)