Activation Error on iPhone 6 Post-Restore: Unavailable Server and iTunes Error 0xE800013

Hello.
I have a problem activating my iPhone 6 after restoring to factory settings. I can't do it on the phone itself or via iTunes.
The phone pops up with an inaccessible server message exactly (iPhone activation error. The iPhone has not been activated; the activation server is unavailable. Try connecting the iPhone to iTunes blabla, etc. (it doesn't matter if via cellular or WiFi). Via iTunes an unknown error pops up at the number 0xE800013. Hands fall, I tried everything I think possible iOS downgrade (it is still 11.02 all the time), restoring the iPhone, updating and everything with miserable result. In iStor the guy said he didn't know what it is and may try to play, but does not guarantee that it will help, and on another site stated that he also does not know and to try again later (XD)
I am asking for help because I have been trying to find it for 2 days and nothing! I have probably done everything that is written on the Internet about this topic.
I tried on iOS 11.01, 02 and today 03 came out, on it also the same.
best regards

Unfortunately, the fault is not in the damaged software. Probably the error is due to damage to the components on the board. In the previous IPH5 model iTunes -1 appeared frequently, the solution was to reheat the systems, thanks to which it regained its efficiency. In your case it will be similar.

Really? I bought this phone as a new one somehow at the beginning of the holiday and I did nothing with it ... It showed no signs of damage, everything worked fine, and now such a thing? Nice balls. How much does such a thing cost?
I sent him to the website, because I have run out of ideas, we'll see what they say ...

The phone had a changeable memory after updating the iOS 11 device has an activation problem to repair the nand memory (please priv)

Upload the latest 11.2.5, these initial 11 software had a problem with the activation, it helped as you changed the language to English, the error on the Polish servers dumped and did not pass on the latest you should not have problems