funnypharmacist and Davod Bradec
Guys, I had this same problem.
I bought a 640 yesterday, just to see if it was worth it to leave my Note 4.
I played around with the phone, loaded some apps, just trying to get a feel for it.
I then downloaded the windows insider app and started the upgrade. It got about 90% complete, and failed, saying that there was a problem with the sd card. (It was almost empty, but I had verified it was working prior to running Windows Insider. I did nothing to try to get the update to load on the sd card.)
I did a hard reset on the phone and then tried to download the update again. At that point, I got the same server error that you are getting, mentioning the date/time error.
Over the past 24 hours, I have done about 6 hard resets, trying different things. (no sd card. no sim card. Not allowing any of the auto software updates that occur after a hard reset.
What finally worked for me was to download Windows Download Recovery Tool to my desktop computer. I loaded it up and plugged my phone into the computer. It recognized the phone and gave me an option to reinstall my software (8.1)
To be fair, the first two times that I tried this using WDRT, it failed, saying that it couldn't update my device. On the third attempt, it was successful doing the reload.
At that point, it went through the normal reset process. When it completed, I downloaded Windows Insider. It started normally, and let me pick the fast track.
I then went and checked for an upgrade in the Settings screen, and an OS upgrade is downloading. The download is at 74% as I type this.
I have no idea if it will eventually work, but I did get around the server error, so maybe you can, also.
I will update when mine is either successful or unsuccessful.
Good luck.
kbanes
FYI - the download and installation finished last night, after what seemed like a couple of hours, but probably just over an hour. Win 10 is a vast improvement over 8.1, but is a little slow on this processor. But I expected that going in.
Now I just have to use it for a week or so to see if it workable for me. I haven't found a decent ebook reader yet. I can live with the work around for Google Music. Not being able to deposit checks is a hindrance.
I suspect that i will give Microsoft 4 or 5 months to see if the app situation is improved, then spring for a 950xl, or whatever the flagship is at that time.
Good Luck guys.
kbanes