High Sierra - the recovery server could not be contacted

Posting the solution to my own issue after hours and hours of trial and error! Hopefully if somebody else comes across this and also could not resolve their issue with the other solutions and advice given on other threads, this might be useful! My theory is that something was corrupted on my Macintosh HD drive.

To summarise, I tried the following that did not work:

• Syncing the date through Terminal
• Using Disk Utility to repair/first aid - no issues
• Using Disk Utility to erase data from both APFS and APFS Encrypted
• Using Disk Utility to restore (nothing to restore apparently)
• Time Machine…
• Reset the NVRAM
• Checked internet connection (everything is fine)

What did work for me:

• Go to disk utility and add a “volume” (you can find instructions for this just by searching “creating a volume in disk utility)
• Turn off machine, whilst restarting hold option, cmd & R (instead of just cmd R). This then gave me the option to install Monterey instead of High Sierra.
• Install Monterey onto the new volume/disk you created.

Hopefully that will work for others!

Just an update on things I am trying currently:

• Created a new disk/volume and restarted again in case it was the Macintosh HD disk that was causing the issue… this time I held down option, cmd R instead of just cmd R to see if it would give me another macOS option as I was on Monterey before and read somewhere this would offer you the latest for your model instead of the default High Sierra. It seems to have given me Monterey to install (already more progress than I’ve made in the last god knows how many hours surfing the forums) and I am currently attempting to install the OS onto the new disk volume I created to trial (named a pretty boring Volume1). It’s telling me there is nearly 3 hours remaining of installation… whether it will work beyond this point is anybody’s guess…