This error is triggered when the nozzle heating element does not heat as expected. Possible causes include:
The silicone sock is not installed on the hotend.
The hotend heating assembly is damaged and needs to be replaced.
Check the hotend and ensure that the silicone sock is correctly installed.
Replace the hotend heating assembly.
Warning: Ensure that the hotend has cooled down completely before proceeding to avoid burns.
Remove the toolhead front cover and correctly install the silicone sock on the hotend.

Replace the hotend heating assembly. For detailed instructions, refer to Wiki Page: Replace i7 Hotend Heating Assembly