Never seen this before -2106F Trying to update my Mac and I’m getting  -2106F. What does this mean!?
A quick Google search led me to this : https://discussions.apple.com/thread/7939592


  The suggestion on the page is to try Internet Recovery mode, and that from there to check the hard disk. There is a comment further down where the user says they were finally able to connect to Internet Recovery


However, it does sound quite possible that you have a bad drive (SSD or hard disk). Contact Apple to see what your options are regarding a replacement/repair.