Help! What does -2003F mean?

Although I had this question before I finally sorted my problem. I tried various methods to install a new Mac OS to MacBook Air 2015 all of which failed. I also had the 2003F error when trying online recovery. What finally worked was, erasing the disk using Mac OS extended Journalled format and GUID partition method. After this final wipe, bootable USB installer worked and installed the Mac OS on my Mac, although it failed several times before. I think this error was related to a disk problem. Happy to hear any comments on this.